essay on man's role in reducing global warming

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• Published: 16 November 2022

Climate change and human behaviour

Nature Human Behaviour volume  6 ,  pages 1441–1442 ( 2022 ) Cite this article

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Climate change is an immense challenge. Human behaviour is crucial in climate change mitigation, and in tackling the arising consequences. In this joint Focus issue between Nature Climate Change and Nature Human Behaviour , we take a closer look at the role of human behaviour in the climate crisis.

In the late 19th century, the scientist (and suffragette) Eunice Newton Foote published a paper suggesting that a build-up of carbon dioxide in the Earth’s atmosphere could cause increased surface temperatures 1 . In the mid-20th century, the British engineer Guy Callendar was the first to concretize the link between carbon dioxide levels and global warming 2 . Now, a century and a half after Foote’s work, there is overwhelming scientific evidence that human behaviour is the main driver of climatic changes and global warming.

The negative effects of rising temperatures on the environment, biodiversity and human health are becoming increasingly noticeable. The years 2020 and 2016 were among the hottest since the record keeping of annual surface temperatures began in 1880 (ref. 3 ). Throughout 2022, the globe was plagued by record-breaking heatwaves. Even regions with a naturally warm climate, such as Pakistan or India, experienced some of their hottest days much earlier in the year — very probably a consequence of climate change 4 . According to the National Centers for Environmental Information of the United States, the surface global temperature during the decade leading up to 2020 was +0.82 °C (+1.48 °F) above the 20th-century average 5 . It is clear that we are facing a global crisis that requires urgent action.

During the Climate Change Conference (COP21) of the United Nations in Paris 2015, 196 parties adopted a legally binding treaty with the aim to limit global warming to ideally 1.5 °C and a maximum of 2 °C, compared to pre-industrial levels. A recent report issued by the UN suggests that we are very unlikely to meet the targets of the Paris Agreement. Instead, current policies are likely to cause temperatures to increase up to 2.8 °C this century 6 . The report suggests that to get on track to 2 °C, new pledges would need to be four times higher — and seven times higher to get on track to 1.5 °C. This November, world leaders will meet for the 27th time to coordinate efforts in facing the climate crisis and mitigating the effects during COP27 in Sharm El-Sheikh, Egypt.

This Focus issue

Human behaviour is not only one of the primary drivers of climate change but also is equally crucial for mitigating the impact of the Anthropocene. In 2022, this was also explicitly acknowledged in the report of the Intergovernmental Panel on Climate Change (IPCC). For the first time, the IPCC directly discussed behavioural, social and cultural dynamics in climate change mitigation 7 . This joint Focus highlights some of the aspects of the human factor that are central in the adaptation to and prevention of a warming climate, and the mitigation of negative consequences. It features original pieces, and also includes a curated collection of already published content from across journals in the Nature Portfolio.

Human behaviour is a neglected factor in climate science

In the light of the empirical evidence for the role of human behaviour in climatic changes, it is curious that the ‘human factor’ has not always received much attention in key research areas, such as climate modelling. For a long time, climate models to predict global warming and emissions did not account for it. This oversight meant that predictions made by these models have differed greatly in their projected rise in temperatures 8 , 9 .

Human behaviour is complex and multidimensional, making it difficult — but crucial — to account for it in climate models. In a Review , Brian Beckage and colleagues thus look at existing social climate models and make recommendations for how these models can better embed human behaviour in their forecasting.

The psychology of climate change

The complexity of humans is also reflected in their psychology. Despite an overwhelming scientific consensus on anthropogenic climate change, research suggests that many people underestimate the effects of it, are sceptical of it or deny its existence altogether. In a Review , Matthew Hornsey and Stephan Lewandowsky look at the psychological origins of such beliefs, as well as the roles of think tanks and political affiliation.

Psychologists are not only concerned with understanding and addressing climate scepticism but are also increasingly worried about mental health consequences. Two narrative Reviews address this topic. Neil Adger et al. discuss the direct and indirect pathways by which climate change affects well-being, and Fiona Charlson et al. adopt a clinical perspective in their piece. They review the literature on the clinical implications of climate change and provide practical suggestions for mental health practitioners.

Individual- and system-level behaviour change

To limit global warming to a minimum, system-level and individual-level behaviour change is necessary. Several pieces in this Focus discuss how such change can be facilitated.

Many interventions for individual behaviour change and for motivating environmental behaviour have been proposed. In a Review , Anne van Valkengoed and colleagues introduce a classification system that links different interventions to the determinants of individual environmental behaviour. Practitioners can use the system to design targeted interventions for behaviour change.

Ideally, interventions are scalable and result in system-level change. Scalability requires an understanding of public perceptions and behaviours, as Mirjam Jenny and Cornelia Betsch explain in a Comment . They draw on the experiences of the COVID-19 pandemic and discuss crucial structures, such as data observatories, for the collection of reliable large-scale data.

Such knowledge is also key for designing robust climate policies. Three Comments in Nature Climate Change look at how insights from behavioural science can inform policy making in areas such as natural-disaster insurance markets , carbon taxing and the assignment of responsibility for supply chain emissions .

Time to act

To buck the trend of rising temperatures, immediate and significant climate action is needed.

Natural disasters have become more frequent and occur at ever-closer intervals. The changing climate is driving biodiversity loss, and affecting human physical and mental health. Unfortunately, the conversations about climate change mitigation are often dominated by Global North and ‘WEIRD’ (Western, educated, industrialized, rich and democratic) perspectives, neglecting the views of countries in the Global South. In a Correspondence , Charles Ogunbode reminds us that climate justice is social justice in the Global South and that, while being a minor contributor to emissions and global warming, this region has to bear many of the consequences.

The fight against climate change is a collective endeavour and requires large-scale solutions. Collective action, however, usually starts with individuals who raise awareness and drive change. In two Q&As, Nature Human Behaviour entered into conversation with people who recognized the power of individual behaviour and took action.

Licypriya Kangujam is a 10-year-old climate activist based in India. She tells us how she hopes to raise the voices of the children of the world in the fight against climate change and connect individuals who want to take action.

Wolfgang Knorr is a former academic who co-founded Faculty for a Future to help academics to transform their careers and address pressing societal issues. In a Q&A , he describes his motivations to leave academia and offers advice on how academics can create impact.

Mitigation of climate change (as well as adaptation to its existing effects) is not possible without human behaviour change, be it on the individual, collective or policy level. The contents of this Focus shed light on the complexities that human behaviour bears, but also point towards future directions. It is the duty of us all to turn this knowledge into action.

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Climate change and human behaviour. Nat Hum Behav 6 , 1441–1442 (2022). https://doi.org/10.1038/s41562-022-01490-9

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Climate change: yes, your individual action does make a difference

PhD Researcher in Environmental Leadership, Cardiff University

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Steve Westlake does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

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What can we do in the face of the climate emergency ? Many say we should drive less, fly less, eat less meat. But others argue that personal actions like this are a pointless drop in the ocean when set against the huge systemic changes that are required to prevent devastating global warming .

It’s a debate that has been raging for decades. Clearly, in terms of global greenhouse gas emissions, a single person’s contribution is basically irrelevant (much like a single vote in an election). But my research, first in my masters and now as part of my PhD, has found that doing something bold like giving up flying can have a wider knock-on effect by influencing others and shifting what’s viewed as “normal”.

In a survey I conducted, half of the respondents who knew someone who has given up flying because of climate change said they fly less because of this example. That alone seemed pretty impressive to me. Furthermore, around three quarters said it had changed their attitudes towards flying and climate change in some way. These effects were increased if a high-profile person had given up flying, such as an academic or someone in the public eye. In this case, around two thirds said they fly less because of this person, and only 7% said it has not affected their attitudes.

I wondered if these impressionable people were already behaving like squeaky-clean environmentalists, but the figures suggested not. The survey respondents fly considerably more than average, meaning they have plenty of potential to fly less because of someone else’s example.

To explore people’s reasoning, I interviewed some of those who had been influenced by a “non-flyer”. They explained that the bold and unusual position to give up flying had: conveyed the seriousness of climate change and flying’s contribution to it; crystallised the link between values and actions; and even reduced feelings of isolation that flying less was a valid and sensible response to climate change. They said that “commitment” and “expertise” were the most influential qualities of the person who had stopped flying.

Letting fly

It’s not all a bed of roses, of course. Flying represents freedom, fun and progress. It boosts the economy and can provide precious travel opportunities. So suggesting that everyone should fly less, which may seem the implicit message of someone who gives up flying because of climate change, can lead to arguments and confrontation. One person for example said that my gently worded survey was “fascist and misinformed”. You don’t get that when you ask about washing-up liquid.

My research also probed ideas of inconsistency and hypocrisy. In short, people hate it . If Barack Obama takes a private jet and has a 14-vehicle entourage to get to a climate change conference, or a celebrity weeps for the climate while rocking a huge carbon footprint , it doesn’t go down well. And if future laws are introduced to reduce flying because of climate change, it looks essential that politicians will have to visibly reduce their flying habits, too. Other research has shown that calls for emissions reductions from climate scientists are much more credible if they themselves walk the talk .

That people are influenced by others is hardly a shocking result. Psychology researchers have spent decades amassing evidence about the powerful effects of social influence , while cultural evolution theory suggests we may have evolved to follow the example of those in prestigious positions because it helped us survive . Pick up any book on leadership in an airport shopping mall and it will likely trumpet the importance of leading by example.

Which raises the question: if our political and business leaders are serious about climate change, shouldn’t they be very visibly reducing their own carbon footprints to set an example to the rest of us? This is now the focus of my research.

But why me?

Weaving an invisible thread through all of the above is the thorny issue of fairness and inequality. The wealthiest 10% of the global population are responsible for 50% of emissions , and plenty of that will be due to flying. In the UK, around 15% of people take 70% of the flights, while half of the population don’t fly at all in any one year. As emissions from aviation become an ever increasing slice of the total (currently around 9% in the UK, 2% globally) this inequality will become harder for everyone to ignore.

In the mean time, the debate about personal vs. collective action will continue. My research supports the arguments that this is a false dichotomy : individual action is part of the collective. So, while you won’t save the world on your own, you might be part of the solution.

Click here to subscribe to our climate action newsletter. Climate change is inevitable. Our response to it isn’t.

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A problem built into our relationship with energy itself. Photo by Ferdinando Scianna/Magnum

Deep warming

Even if we ‘solve’ global warming, we face an older, slower problem. waste heat could radically alter earth’s future.

by Mark Buchanan   + BIO

The world will be transformed. By 2050, we will be driving electric cars and flying in aircraft running on synthetic fuels produced through solar and wind energy. New energy-efficient technologies, most likely harnessing artificial intelligence, will dominate nearly all human activities from farming to heavy industry. The fossil fuel industry will be in the final stages of a terminal decline. Nuclear fusion and other new energy sources may have become widespread. Perhaps our planet will even be orbited by massive solar arrays capturing cosmic energy from sunlight and generating seemingly endless energy for all our needs.

That is one possible future for humanity. It’s an optimistic view of how radical changes to energy production might help us slow or avoid the worst outcomes of global warming. In a report from 1965, scientists from the US government warned that our ongoing use of fossil fuels would cause global warming with potentially disastrous consequences for Earth’s climate. The report, one of the first government-produced documents to predict a major crisis caused by humanity’s large-scale activities, noted that the likely consequences would include higher global temperatures, the melting of the ice caps and rising sea levels. ‘Through his worldwide industrial civilisation,’ the report concluded, ‘Man is unwittingly conducting a vast geophysical experiment’ – an experiment with a highly uncertain outcome, but clear and important risks for life on Earth.

Since then, we’ve dithered and doubted and argued about what to do, but still have not managed to take serious action to reduce greenhouse gas emissions, which continue to rise. Governments around the planet have promised to phase out emissions in the coming decades and transition to ‘green energy’. But global temperatures may be rising faster than we expected: some climate scientists worry that rapid rises could create new problems and positive feedback loops that may accelerate climate destabilisation and make parts of the world uninhabitable long before a hoped-for transition is possible.

Despite this bleak vision of the future, there are reasons for optimists to hope due to progress on cleaner sources of renewable energy, especially solar power. Around 2010, solar energy generation accounted for less than 1 per cent of the electricity generated by humanity. But experts believe that, by 2027, due to falling costs, better technology and exponential growth in new installations, solar power will become the largest global energy source for producing electricity. If progress on renewables continues, we might find a way to resolve the warming problem linked to greenhouse gas emissions. By 2050, large-scale societal and ecological changes might have helped us avoid the worst consequences of our extensive use of fossil fuels.

It’s a momentous challenge. And it won’t be easy. But this story of transformation only hints at the true depth of the future problems humanity will confront in managing our energy use and its influence over our climate.

As scientists are gradually learning, even if we solve the immediate warming problem linked to the greenhouse effect, there’s another warming problem steadily growing beneath it. Let’s call it the ‘deep warming’ problem. This deeper problem also raises Earth’s surface temperature but, unlike global warming, it has nothing to do with greenhouse gases and our use of fossil fuels. It stems directly from our use of energy in all forms and our tendency to use more energy over time – a problem created by the inevitable waste heat that is generated whenever we use energy to do something. Yes, the world may well be transformed by 2050. Carbon dioxide levels may stabilise or fall thanks to advanced AI-assisted technologies that run on energy harvested from the sun and wind. And the fossil fuel industry may be taking its last breaths. But we will still face a deeper problem. That’s because ‘deep warming’ is not created by the release of greenhouse gases into the atmosphere. It’s a problem built into our relationship with energy itself.

F inding new ways to harness more energy has been a constant theme of human development. The evolution of humanity – from early modes of hunter-gathering to farming and industry – has involved large systematic increases in our per-capita energy use. The British historian and archaeologist Ian Morris estimates, in his book Foragers, Farmers, and Fossil Fuels: How Human Values Evolve (2015), that early human hunter-gatherers, living more than 10,000 years ago, ‘captured’ around 5,000 kcal per person per day by consuming food, burning fuel, making clothing, building shelter, or through other activities. Later, after we turned to farming and enlisted the energies of domesticated animals, we were able to harness as much as 30,000 kcal per day. In the late 17th century , the exploitation of coal and steam power marked another leap: by 1970, the use of fossil fuels allowed humans to consume some 230,000 kcal per person per day. (When we think about humanity writ large as ‘humans’, it’s important to acknowledge that the average person in the wealthiest nations consumes up to 100 times more energy than the average person in the poorest nations.) As the global population has risen and people have invented new energy-dependent technologies, our global energy use has continued to climb.

In many respects, this is great. We can now do more with less effort and achieve things that were unimaginable to the 17th-century inventors of steam engines, let alone to our hominin ancestors. We’ve made powerful mining machines, superfast trains, lasers for use in telecommunications and brain-imaging equipment. But these creations, while helping us, are also subtly heating the planet.

All the energy we humans use – to heat our homes, run our factories, propel our automobiles and aircraft, or to run our electronics – eventually ends up as heat in the environment. In the shorter term, most of the energy we use flows directly into the environment. It gets there through hot exhaust gases, friction between tires and roads, the noises generated by powerful engines, which spread out, dissipate, and eventually end up as heat. However, a small portion of the energy we use gets stored in physical changes, such as in new steel, plastic or concrete. It’s stored in our cities and technologies. In the longer term, as these materials break down, the energy stored inside also finds its way into the environment as heat. This is a direct consequence of the well-tested principles of thermodynamics.

Waste heat will pose a problem that is every bit as serious as global warming from greenhouse gases

In the early decades of the 21st century , this heat created by simply using energy, known as ‘waste heat’, is not so serious. It’s equivalent to roughly 2 per cent of the planetary heating imbalance caused by greenhouse gases – for now. But, with the passing of time, the problem is likely to get much more serious. That’s because humans have a historical tendency to consistently discover and produce things, creating entirely new technologies and industries in the process: domesticated animals for farming; railways and automobiles; global air travel and shipping; personal computers, the internet and mobile phones. The result of such activities is that we end up using more and more energy, despite improved energy efficiency in nearly every area of technology.

During the past two centuries at least (and likely for much longer), our yearly energy use has doubled roughly every 30 to 50 years . Our energy use seems to be growing exponentially, a trend that shows every sign of continuing. We keep finding new things to do and almost everything we invent requires more and more energy: consider the enormous energy demands of cryptocurrency mining or the accelerating energy requirements of AI.

If this historical trend continues, scientists estimate waste heat will pose a problem in roughly 150-200 years that is every bit as serious as the current problem of global warming from greenhouse gases. However, deep heating will be more pernicious as we won’t be able to avoid it by merely shifting from one kind energy to another. A profound problem will loom before us: can we set strict limits on all the energy we use? Can we reign in the seemingly inexorable expansion of our activities to avoid destroying our own environment?

Deep warming is a problem hiding beneath global warming, but one that will become prominent if and when we manage to solve the more pressing issue of greenhouse gases. It remains just out of sight, which might explain why scientists only became concerned about the ‘waste heat’ problem around 15 years ago.

O ne of the first people to describe the problem is the Harvard astrophysicist Eric Chaisson, who discussed the issue of waste heat in a paper titled ‘Long-Term Global Heating from Energy Usage’ (2008). He concluded that our technological society may be facing a fundamental limit to growth due to ‘unavoidable global heating … dictated solely by the second law of thermodynamics, a biogeophysical effect often ignored when estimating future planetary warming scenarios’. When I emailed Chaisson to learn more, he told me the history of his thinking on the problem:

It was on a night flight, Paris-Boston [circa] 2006, after a UNESCO meeting on the environment when it dawned on me that the IPCC were overlooking something. While others on the plane slept, I crunched some numbers literally on the back of an envelope … and then hoped I was wrong, that is, hoped that I was incorrect in thinking that the very act of using energy heats the air, however slightly now.

The transformation of energy into heat is among the most ubiquitous processes of physics

Chaisson drafted the idea up as a paper and sent it to an academic journal. Two anonymous reviewers were eager for it to be published. ‘A third tried his damnedest to kill it,’ Chaisson said, the reviewer claiming the findings were ‘irrelevant and distracting’. After it was finally published, the paper got some traction when it was covered by a journalist and ran as a feature story on the front page of The Boston Globe . The numbers Chaisson crunched, predictions of our mounting waste heat, were even run on a supercomputer at the US National Center for Atmospheric Research, by Mark Flanner, a professor of earth system science. Flanner, Chaisson suspected at the time, was likely ‘out to prove it wrong’. But, ‘after his machine crunched for many hours’, he saw the same results that Chaisson had written on the back of an envelope that night in the plane.

Around the same time, also in 2008, two engineers, Nick Cowern and Chihak Ahn, wrote a research paper entirely independent of Chaisson’s work, but with similar conclusions. This was how I first came across the problem. Cowern and Ahn’s study estimated the total amount of waste heat we’re currently releasing to the environment, and found that it is, right now, quite small. But, like Chaisson, they acknowledged that the problem would eventually become serious unless steps were taken to avoid it.

That’s some of the early history of thinking in this area. But these two papers, and a few other analyses since, point to the same unsettling conclusion: what I am calling ‘deep warming’ will be a big problem for humanity at some point in the not-too-distant future. The precise date is far from certain. It might be 150 years , or 400, or 800, but it’s in the relatively near future, not the distant future of, say, thousands or millions of years. This is our future.

T he transformation of energy into heat is among the most ubiquitous processes of physics. As cars drive down roads, trains roar along railways, planes cross the skies and industrial plants turn raw materials into refined products, energy gets turned into heat, which is the scientific word for energy stored in the disorganised motions of molecules at the microscopic level. As a plane flies from Paris to Boston, it burns fuel and thrusts hot gases into the air, generates lots of sound and stirs up contrails. These swirls of air give rise to swirls on smaller scales which in turn make smaller ones until the energy ultimately ends up lost in heat – the air is a little warmer than before, the molecules making it up moving about a little more vigorously. A similar process takes place when energy is used by the tiny electrical currents inside the microchips of computers, silently carrying out computations. Energy used always ends up as heat. Decades ago, research by the IBM physicist Rolf Landauer showed that a computation involving even a single computing bit will release a certain minimum amount of heat to the environment.

How this happens is described by the laws of thermodynamics, which were described in the mid-19th century by scientists including Sadi Carnot in France and Rudolf Clausius in Germany. Two key ‘laws’ summarise its main principles.

The first law of thermodynamics simply states that the total quantity of energy never changes but is conserved. Energy, in other words, never disappears, but only changes form. The energy initially stored in an aircraft’s fuel, for example, can be changed into the energetic motion of the plane. Turn on an electric heater, and energy initially held in electric currents gets turned into heat, which spreads into the air, walls and fabric of your house. The total energy remains the same, but it markedly changes form.

We’re generating waste heat all the time with everything we do

The second law of thermodynamics, equally important, is more subtle and states that, in natural processes, the transformation of energy always moves from more organised and useful forms to less organised and less useful forms. For an aircraft, the energy initially concentrated in jet fuel ends up dissipated in stirred-up winds, sounds and heat spread over vast areas of the atmosphere in a largely invisible way. It’s the same with the electric heater: the organised useful energy in the electric currents gets dissipated and spread into the low-grade warmth of the walls, then leaks into the outside air. Although the amount of energy remains the same, it gradually turns into less organised, less usable forms. The end point of the energy process produces waste heat. And we’re generating it all the time with everything we do.

Data on world energy consumption shows that, collectively, all humans on Earth are currently using about 170,000 terawatt-hours (TWh), which is a lot of energy in absolute terms – a terawatt-hour is the total energy consumed in one hour by any process using energy at a rate of 1 trillion watts. This huge number isn’t surprising, as it represents all the energy being used every day by the billions of cars and homes around the world, as well as by industry, farming, construction, air traffic and so on. But, in the early 21st century , the warming from this energy is still much less than the planetary heating due to greenhouse gases.

Concentrations of greenhouse gases such as CO 2 and methane are quite small, and only make a fractional difference to how much of the Sun’s energy gets trapped in the atmosphere, rather than making it back out to space. Even so, this fractional difference has a huge effect because the stream of energy arriving from the Sun to Earth is so large. Current estimates of this greenhouse energy imbalance come to around 0.87 W per square meter, which translates into a total energy figure about 50 times larger than our waste heat. That’s reassuring. But as Cowern and Ahn wrote in their 2008 paper, things aren’t likely to stay this way over time because our energy usage keeps rising. Unless, that is, we can find some radical way to break the trend of using ever more energy.

O ne common objection to the idea of the deep warming is to claim that the problem won’t really arise. ‘Don’t worry,’ someone might say, ‘with efficient technology, we’re going to find ways to stop using more energy; though we’ll end up doing more things in the future, we’ll use less energy.’ This may sound plausible at first, because we are indeed getting more efficient at using energy in most areas of technology. Our cars, appliances and laptops are all doing more with less energy. If efficiency keeps improving, perhaps we can learn to run these things with almost no energy at all? Not likely, because there are limits to energy efficiency.

Over the past few decades, the efficiency of heating in homes – including oil and gas furnaces, and boilers used to heat water – has increased from less than 50 per cent to well above 90 per cent of what is theoretically possible. That’s good news, but there’s not much more efficiency to be realised in basic heating. The efficiency of lighting has also vastly improved, with modern LED lighting turning something like 70 per cent of the applied electrical energy into light. We will gain some efficiencies as older lighting gets completely replaced by LEDs, but there’s not a lot of room left for future efficiency improvements. Similar efficiency limits arise in the growing or cooking of food; in the manufacturing of cars, bikes and electronic devices; in transportation, as we’re taken from place to place; in the running of search engines, translation software, GPT-4 or other large-language models.

Even if we made significant improvements in the efficiencies of these technologies, we will only have bought a little time. These changes won’t delay by much the date when deep warming becomes a problem we must reckon with.

Optimising efficiencies is just a temporary reprieve, not a radical change in our human future

As a thought experiment, suppose we could immediately improve the energy efficiency of everything we do by a factor of 10 – a fantastically optimistic proposal. That is, imagine the energy output of humans on Earth has been reduced 10 times , from 170,000 TWh to 17,000 TWh . If our energy use keeps expanding, doubling every 30-50 years or so (as it has for centuries), then a 10-fold increase in waste heat will happen in just over three doubling times, which is about 130 years : 17,000 TWh doubles to 34,000 TWh , which doubles to 68,000 TWh , which doubles to 136,000 TWh , and so on. All those improvements in energy efficiency would quickly evaporate. The date when deep warming hits would recede by 130 years or so, but not much more. Optimising efficiencies is just a temporary reprieve, not a radical change in our human future.

Improvements in energy efficiency can also have an inverse effect on our overall energy use. It’s easy to think that if we make a technology more efficient, we’ll then use less energy through the technology. But economists are deeply aware of a paradoxical effect known as ‘rebound’, whereby improved energy efficiency, by making the use of a technology cheaper, actually leads to more widespread use of that technology – and more energy use too. The classic example, as noted by the British economist William Stanley Jevons in his book The Coal Question (1865), is the invention of the steam engine. This new technology could extract energy from burning coal more efficiently, but it also made possible so many new applications that the use of coal increased. A recent study by economists suggests that, across the economy, such rebound effects might easily swallow at least 50 per cent of any efficiency gains in energy use. Something similar has already happened with LED lights, for which people have found thousands of new uses.

If gains in efficiency won’t buy us lots of time, how about other factors, such as a reduction of the global population? Scientists generally believe that the current human population of more than 8 billion people is well beyond the limits of our finite planet, especially if a large fraction of this population aspires to the resource-intensive lifestyles of wealthy nations. Some estimates suggest that a more sustainable population might be more like 2 billion , which could reduce energy use significantly, potentially by a factor of three or four. However, this isn’t a real solution: again, as with the example of improved energy efficiency, a one-time reduction of our energy consumption by a factor of three will quickly be swallowed up by an inexorable rise in energy use. If Earth’s population were suddenly reduced to 2 billion – about a quarter of the current population – our energy gains would initially be enormous. But those gains would be erased in two doubling times, or roughly 60-100 years , as our energy demands would grow fourfold.

S o, why aren’t more people talking about this? The deep warming problem is starting to get more attention. It was recently mentioned on Twitter by the German climate scientist Stefan Rahmstorf, who cautioned that nuclear fusion, despite excitement over recent advances, won’t arrive in time to save us from our waste heat, and might make the problem worse. By providing another cheap source of energy, fusion energy could accelerate both the growth of our energy use and the reckoning of deep warming. A student of Rahmstorf’s, Peter Steiglechner, wrote his master’s thesis on the problem in 2018. Recognition of deep warming and its long-term implications for humanity is spreading. But what can we do about the problem?

Avoiding or delaying deep warming will involve slowing the rise of our waste heat, which means restricting the amount of energy we use and also choosing energy sources that exacerbate the problem as little as possible. Unlike the energy from fossil fuels or nuclear power, which add to our waste energy burden, renewable energy sources intercept energy that is already on its way to Earth, rather than producing additional waste heat. In this sense, the deep warming problem is another reason to pursue renewable energy sources such as solar or wind rather than alternatives such as nuclear fusion, fission or even geothermal power. If we derive energy from any of these sources, we’re unleashing new flows of energy into the Earth system without making a compensating reduction. As a result, all such sources will add to the waste heat problem. However, if renewable sources of energy are deployed correctly, they need not add to our deposition of waste heat in the environment. By using this energy, we produce no more waste heat than would have been created by sunlight in the first place.

Take the example of wind energy. Sunlight first stirs winds into motion by heating parts of the planet unequally, causing vast cells of convection. As wind churns through the atmosphere, blows through trees and over mountains and waves, most of its energy gets turned into heat, ending up in the microscopic motions of molecules. If we harvest some of this wind energy through turbines, it will also be turned into heat in the form of stored energy. But, crucially, no more heat is generated than if there had been no turbines to capture the wind.

The same can hold true for solar energy. In an array of solar cells, if each cell only collects the sunlight falling on it – which would ordinarily have been absorbed by Earth’s surface – then the cells don’t alter how much waste heat gets produced as they generate energy. The light that would have warmed Earth’s surface instead goes into the solar cells, gets used by people for some purpose, and then later ends up as heat. In this way we reduce the amount of heat being absorbed by Earth by precisely the same amount as the energy we are extracting for human use. We are not adding to overall planetary heating. This keeps the waste energy burden unchanged, at least in the relatively near future, even if we go on extracting and using ever larger amounts of energy.

Covering deserts in dark panels would absorb a lot more energy than the desert floor

Chaisson summarised the problem quite clearly in 2008:

I’m now of the opinion … that any energy that’s dug up on Earth – including all fossil fuels of course, but also nuclear and ground-sourced geothermal – will inevitably produce waste heat as a byproduct of humankind’s use of energy. The only exception to that is energy arriving from beyond Earth, this is energy here and now and not dug up, namely the many solar energies (plural) caused by the Sun’s rays landing here daily … The need to avoid waste heat is indeed the single, strongest, scientific argument to embrace solar energies of all types.

But not just any method of gathering solar energy will avoid the deep warming problem. Doing so requires careful engineering. For example, covering deserts with solar panels would add to planetary heating because deserts reflect a lot of incident light back out to space, so it is never absorbed by Earth (and therefore doesn’t produce waste heat). Covering deserts in dark panels would absorb a lot more energy than the desert floor and would heat the planet further.

We’ll also face serious problems in the long run if our energy appetite keeps increasing. Futurists dream of technologies deployed in space where huge panels would absorb sunlight that would otherwise have passed by Earth and never entered our atmosphere. Ultimately, they believe, this energy could be beamed down to Earth. Like nuclear energy, such technologies would add an additional energy source to the planet without any compensating removal of heating from the sunlight currently striking our planet’s surface. Any effort to produce more energy than is normally available from sunlight at Earth’s surface will only make our heating problems worse.

D eep warming is simply a consequence of the laws of physics and our inquisitive nature. It seems to be in our nature to constantly learn and develop new things, changing our environment in the process. For thousands of years, we have harvested and exploited ever greater quantities of energy in this pursuit, and we appear poised to continue along this path with the rapidly expanding use of renewable energy sources – and perhaps even more novel sources such as nuclear fusion. But this path cannot proceed indefinitely without consequences.

The logic that more energy equals more warming sets up a profound dilemma for our future. The laws of physics and the habits ingrained in us from our long evolutionary history are steering us toward trouble. We may have a technological fix for greenhouse gas warming – just shift from fossil fuels to cleaner energy sources – but there is no technical trick to get us out of the deep warming problem. That won’t stop some scientists from trying.

Perhaps, believing that humanity is incapable of reducing its energy usage, we’ll adopt a fantastic scheme to cool the planet, such as planetary-scale refrigeration or using artificially engineered tornadoes to transport heat from Earth’s surface to the upper atmosphere where it can be radiated away to space. As far-fetched as such approaches sound, scientists have given some serious thought to these and other equally bizarre ideas, which seem wholly in the realm of science fiction. They’re schemes that will likely make the problem worse not better.

We will need to transform the human story. It must become a story of doing less, not more

I see several possibilities for how we might ultimately respond. As with greenhouse gas warming, there will probably be an initial period of disbelief, denial and inaction, as we continue with unconstrained technological advance and growing energy use. Our planet will continue warming. Sooner or later, however, such warming will lead to serious disruptions of the Earth environment and its ecosystems. We won’t be able to ignore this for long, and it may provide a natural counterbalance to our energy use, as our technical and social capacity to generate and use ever more energy will be eroded. We may eventually come to some uncomfortable balance in which we just scrabble out a life on a hot, compromised planet because we lack the moral and organisational ability to restrict our energy use enough to maintain a sound environment.

An alternative would require a radical break with our past: using less energy. Finding a way to use less energy would represent a truly fundamental rupture with all of human history, something entirely novel. A rupture of this magnitude won’t come easily. However, if we could learn to view restrictions on our energy use as a non-negotiable element of life on Earth, we may still be able to do many of the things that make us essentially human: learning, discovering, inventing, creating. In this scenario, any helpful new technology that comes into use and begins using lots of energy would require a balancing reduction in energy use elsewhere. In such a way, we might go on with the future being perpetually new, and possibly better.

None of this is easily achieved and will likely mirror our current struggles to come to agreements on greenhouse gas heating. There will be vicious squabbles, arguments and profound polarisation, quite possibly major wars. Humanity will never have faced a challenge of this magnitude, and we won’t face up to it quickly or easily, I expect. But we must. Planetary heating is in our future – the very near future and further out as well. Many people will find this conclusion surprisingly hard to swallow, perhaps because it implies fundamental restrictions on our future here on Earth: we can’t go on forever using more and more energy, and, at the same time, expecting the planet’s climate to remain stable.

The world will likely be transformed by 2050. And, sometime after that, we will need to transform the human story. The narrative arc of humanity must become a tale of continuing innovation and learning, but also one of careful management. It must become a story, in energy terms, of doing less, not more. There’s no technology for entirely escaping waste heat, only techniques.

This is important to remember as we face up to the extremely urgent challenge of heating linked to fossil-fuel use and greenhouse gases. Global warming is just the beginning of our problems. It’s a testing ground to see if we can manage an intelligent and coordinated response. If we can handle this challenge, we might be better prepared, more capable and resilient as a species to tackle an even harder one.

Stories and literature

Her blazing world

Margaret Cavendish’s boldness and bravery set 17th-century society alight, but is she a feminist poster-girl for our times?

Francesca Peacock

Ecology and environmental sciences

To take care of the Earth, humans must recognise that we are both a part of the animal kingdom and its dominant power

Hugh Desmond

Mental health

The last great stigma

Workers with mental illness experience discrimination that would be unthinkable for other health issues. Can this change?

Pernille Yilmam

Quantum theory

Quantum dialectics

When quantum mechanics posed a threat to the Marxist doctrine of materialism, communist physicists sought to reconcile the two

Jim Baggott

Folk music was never green

Don’t be swayed by the sound of environmental protest: these songs were first sung in the voice of the cutter, not the tree

Richard Smyth

Nations and empires

A United States of Europe

A free and unified Europe was first imagined by Italian radicals in the 19th century. Could we yet see their dream made real?

Fernanda Gallo

Scientific Consensus

It’s important to remember that scientists always focus on the evidence, not on opinions. Scientific evidence continues to show that human activities ( primarily the human burning of fossil fuels ) have warmed Earth’s surface and its ocean basins, which in turn have continued to impact Earth’s climate . This is based on over a century of scientific evidence forming the structural backbone of today's civilization.

NASA Global Climate Change presents the state of scientific knowledge about climate change while highlighting the role NASA plays in better understanding our home planet. This effort includes citing multiple peer-reviewed studies from research groups across the world, 1 illustrating the accuracy and consensus of research results (in this case, the scientific consensus on climate change) consistent with NASA’s scientific research portfolio.

With that said, multiple studies published in peer-reviewed scientific journals 1 show that climate-warming trends over the past century are extremely likely due to human activities. In addition, most of the leading scientific organizations worldwide have issued public statements endorsing this position. The following is a partial list of these organizations, along with links to their published statements and a selection of related resources.

American Scientific Societies

Statement on climate change from 18 scientific associations.

"Observations throughout the world make it clear that climate change is occurring, and rigorous scientific research demonstrates that the greenhouse gases emitted by human activities are the primary driver." (2009) 2

American Association for the Advancement of Science

"Based on well-established evidence, about 97% of climate scientists have concluded that human-caused climate change is happening." (2014) 3

American Chemical Society

"The Earth’s climate is changing in response to increasing concentrations of greenhouse gases (GHGs) and particulate matter in the atmosphere, largely as the result of human activities." (2016-2019) 4

American Geophysical Union

"Based on extensive scientific evidence, it is extremely likely that human activities, especially emissions of greenhouse gases, are the dominant cause of the observed warming since the mid-20th century. There is no alterative explanation supported by convincing evidence." (2019) 5

American Medical Association

"Our AMA ... supports the findings of the Intergovernmental Panel on Climate Change’s fourth assessment report and concurs with the scientific consensus that the Earth is undergoing adverse global climate change and that anthropogenic contributions are significant." (2019) 6

American Meteorological Society

"Research has found a human influence on the climate of the past several decades ... The IPCC (2013), USGCRP (2017), and USGCRP (2018) indicate that it is extremely likely that human influence has been the dominant cause of the observed warming since the mid-twentieth century." (2019) 7

American Physical Society

"Earth's changing climate is a critical issue and poses the risk of significant environmental, social and economic disruptions around the globe. While natural sources of climate variability are significant, multiple lines of evidence indicate that human influences have had an increasingly dominant effect on global climate warming observed since the mid-twentieth century." (2015) 8

The Geological Society of America

"The Geological Society of America (GSA) concurs with assessments by the National Academies of Science (2005), the National Research Council (2011), the Intergovernmental Panel on Climate Change (IPCC, 2013) and the U.S. Global Change Research Program (Melillo et al., 2014) that global climate has warmed in response to increasing concentrations of carbon dioxide (CO2) and other greenhouse gases ... Human activities (mainly greenhouse-gas emissions) are the dominant cause of the rapid warming since the middle 1900s (IPCC, 2013)." (2015) 9

Science Academies

International academies: joint statement.

"Climate change is real. There will always be uncertainty in understanding a system as complex as the world’s climate. However there is now strong evidence that significant global warming is occurring. The evidence comes from direct measurements of rising surface air temperatures and subsurface ocean temperatures and from phenomena such as increases in average global sea levels, retreating glaciers, and changes to many physical and biological systems. It is likely that most of the warming in recent decades can be attributed to human activities (IPCC 2001)." (2005, 11 international science academies) 1 0

U.S. National Academy of Sciences

"Scientists have known for some time, from multiple lines of evidence, that humans are changing Earth’s climate, primarily through greenhouse gas emissions." 1 1

U.S. Government Agencies

U.s. global change research program.

"Earth’s climate is now changing faster than at any point in the history of modern civilization, primarily as a result of human activities." (2018, 13 U.S. government departments and agencies) 12

Intergovernmental Bodies

Intergovernmental panel on climate change.

“It is unequivocal that the increase of CO 2 , methane, and nitrous oxide in the atmosphere over the industrial era is the result of human activities and that human influence is the principal driver of many changes observed across the atmosphere, ocean, cryosphere, and biosphere. “Since systematic scientific assessments began in the 1970s, the influence of human activity on the warming of the climate system has evolved from theory to established fact.” 1 3-17

Other Resources

List of worldwide scientific organizations.

The following page lists the nearly 200 worldwide scientific organizations that hold the position that climate change has been caused by human action. http://www.opr.ca.gov/facts/list-of-scientific-organizations.html

U.S. Agencies

The following page contains information on what federal agencies are doing to adapt to climate change. https://www.c2es.org/site/assets/uploads/2012/02/climate-change-adaptation-what-federal-agencies-are-doing.pdf

Technically, a “consensus” is a general agreement of opinion, but the scientific method steers us away from this to an objective framework. In science, facts or observations are explained by a hypothesis (a statement of a possible explanation for some natural phenomenon), which can then be tested and retested until it is refuted (or disproved).

As scientists gather more observations, they will build off one explanation and add details to complete the picture. Eventually, a group of hypotheses might be integrated and generalized into a scientific theory, a scientifically acceptable general principle or body of principles offered to explain phenomena.

1. K. Myers, et al, "Consensus revisited: quantifying scientific agreement on climate change and climate expertise among Earth scientists 10 years later", Environmental Research Letters Vol.16 No. 10, 104030 (20 October 2021); DOI:10.1088/1748-9326/ac2774 M. Lynas, et al, "Greater than 99% consensus on human caused climate change in the peer-reviewed scientific literature", Environmental Research Letters Vol.16 No. 11, 114005 (19 October 2021); DOI:10.1088/1748-9326/ac2966 J. Cook et al., "Consensus on consensus: a synthesis of consensus estimates on human-caused global warming", Environmental Research Letters Vol. 11 No. 4, (13 April 2016); DOI:10.1088/1748-9326/11/4/048002 J. Cook et al., "Quantifying the consensus on anthropogenic global warming in the scientific literature", Environmental Research Letters Vol. 8 No. 2, (15 May 2013); DOI:10.1088/1748-9326/8/2/024024 W. R. L. Anderegg, “Expert Credibility in Climate Change”, Proceedings of the National Academy of Sciences Vol. 107 No. 27, 12107-12109 (21 June 2010); DOI: 10.1073/pnas.1003187107 P. T. Doran & M. K. Zimmerman, "Examining the Scientific Consensus on Climate Change", Eos Transactions American Geophysical Union Vol. 90 Issue 3 (2009), 22; DOI: 10.1029/2009EO030002 N. Oreskes, “Beyond the Ivory Tower: The Scientific Consensus on Climate Change”, Science Vol. 306 no. 5702, p. 1686 (3 December 2004); DOI: 10.1126/science.1103618

2. Statement on climate change from 18 scientific associations (2009)

3. AAAS Board Statement on Climate Change (2014)

4. ACS Public Policy Statement: Climate Change (2016-2019)

5. Society Must Address the Growing Climate Crisis Now (2019)

6. Global Climate Change and Human Health (2019)

7. Climate Change: An Information Statement of the American Meteorological Society (2019)

8. American Physical Society (2021)

9. GSA Position Statement on Climate Change (2015)

10. Joint science academies' statement: Global response to climate change (2005)

11. Climate at the National Academies

12. Fourth National Climate Assessment: Volume II (2018)

13. IPCC Fifth Assessment Report, Summary for Policymakers, SPM 1.1 (2014)

14. IPCC Fifth Assessment Report, Summary for Policymakers, SPM 1 (2014)

15. IPCC Sixth Assessment Report, Working Group 1 (2021)

16. IPCC Sixth Assessment Report, Working Group 2 (2022)

17. IPCC Sixth Assessment Report, Working Group 3 (2022)

Discover More Topics From NASA

Explore Earth Science

Earth Science in Action

Earth Science Data

Facts About Earth

Goal 13: Take urgent action to combat climate change and its impacts

Every person, in every country in every continent will be impacted in some shape or form by climate change. There is a climate cataclysm looming, and we are underprepared for what this could mean.

Climate change is caused by human activities and threatens life on earth as we know it. With rising greenhouse gas emissions, climate change is occurring at rates much faster than anticipated. Its impacts can be devastating and include extreme and changing weather patterns and rising sea levels.

If left unchecked, climate change will undo a lot of the development progress made over the past years. It will also provoke mass migrations that will lead to instability and wars.

To limit global warming to 1.5°C above pre- industrial levels, emissions must already be decreasing and need to be cut by almost half by 2030, just seven years away. But, we are drastically off track from this target.

Urgent and transformative going beyond mere plans and promises are crucial. It requires raising ambition, covering entire economies and moving towards climate-resilient development, while outlining a clear path to achieve net-zero emissions. Immediate measures are necessary to avoid catastrophic consequences and secure a sustainable future for generations to come.

The climate crisis continues unabated as the global community shies away from the full commitment required for its reversal. 2010 – 2019 was the warmest decade ever recorded, bringing with it massive wildfires, hurricanes, droughts, floods and other climate disasters across continents.

Climate change is disrupting national economies and affecting lives and livelihoods, especially for the most vulnerable.

Between 2010 and 2020, highly vulnerable regions, home to approximately 3.3–3.6 billion people, experienced 15 x higher human mortality rates from floods, droughts and storms compared to regions with very low vulnerability.

What happens if you don’t take action?

If left unchecked, climate change will cause average global temperatures to increase beyond 3°C, and will adversely affect every ecosystem. Already, we are seeing how climate change can exacerbate storms and disasters, and threats such as food and water scarcity, which can lead to conflict. Doing nothing will end up costing us a lot more than if we take action now.

Solving the problem

To address climate change, we have to vastly raise our ambition at all levels. Much is happening around the world – investments in renewable energy have soared. But more needs to be done. The world must transform its energy, industry, transport, food, agriculture and forestry systems to ensure that we can limit global temperature rise to well below 2°C, maybe even 1.5°C. In December 2015, the world took a significant first step by adopting the Paris Agreement, in which all countries committed to take action to address climate change. However, more actions are critically needed in order to meet the targets.

Businesses and investors need to ensure emissions are lowered, not just because it is the right thing to do, but because it makes economic and business sense as well.

Are we investing enough to combat climate change?

According to the UNFCCC, global climate finance flows reached an annual average of $803 billion in 2019–2020, a 12 per cent increase compared to prior years. However, this still falls short of the levels needed to limit warming, and fossil-fuel-related flows exceeded climate financing for adaptation and mitigation in 2020.

In 2019, at least 120 of the 153 developing countries had undertaken activities to formulate and implement National Adaptation Plans to enhance climate adaptation and resilience, an increase of 29 countries over the previous year. Furthermore, progress in meeting the 2020 disaster risk reduction target has been slow.

What can I do to help?

There are many things that each of us can do as individuals. To find out what you can do, go to: www.un.org/en/actnow

To read more about the UN’s efforts on climate change: un.org/climatechange

Facts and figures

Goal 13 targets.

• With a climate cataclysm looming, the pace and scale of current climate action plans are wholly insufficient to effectively tackle climate change. Increasingly frequent and intense extreme weather events are already impacting every region on Earth. Rising temperatures will escalate these hazards further, posing grave risks.
• The Intergovernmental Panel on Climate Change (IPCC) emphasizes that deep, rapid and sustained reductions in greenhouse gas (GHG) emissions are essential in all sectors, beginning now and continuing throughout this decade. To limit global warming to 1.5°C above pre- industrial levels, emissions must already be decreasing and need to be cut by almost half by 2030, just seven years away.
• Urgent and transformative action is crucial, going beyond mere plans and promises. It requires raising ambition, covering entire economies and moving towards climate-resilient development, while outlining a clear path to achieve net-zero emissions. Time is running out, and immediate measures are necessary to avoid catastrophic consequences and secure a sustainable future for generations to come.

Source: The Sustainable Development Goals Report 2023

13.1  Strengthen resilience and adaptive capacity to climate-related hazards and natural disasters in all countries

13.2  Integrate climate change measures into national policies, strategies and planning

13.3  Improve education, awareness-raising and human and institutional capacity on climate change mitigation, adaptation, impact reduction and early warning

13.A  Implement the commitment undertaken by developed-country parties to the United Nations Framework Convention on Climate Change to a goal of mobilizing jointly $100 billion annually by 2020 from all sources to address the needs of developing countries in the context of meaningful mitigation actions and transparency on implementation and fully operationalize the Green Climate Fund through its capitalization as soon as possible

13.B  Promote mechanisms for raising capacity for effective climate change-related planning and management in least developed countries and small island developing States, including focusing on women, youth and local and marginalized communities

*Acknowledging that the United Nations Framework Convention on Climate Change is the primary international, intergovernmental forum for negotiating the global response to climate change.

UN and climate change site

UN Framework on the Convention on Climate Change

World Meteorological Organization

UN Population Fund

UN Environment – Climate Change

Intergovernmental panel on Climate Change

FAO – Climate

Fast Facts: Climate Action

Infographic: Climate Action

Climate Action Summit 2019

With global emissions are reaching record levels and showing no sign of peaking, UN Secretary-General António Guterres called on all leaders to come to New York on 23 September 2019 for the Climate Action Summit with concrete, realistic plans to enhance their nationally determined contributions by 2020, in line with reducing greenhouse gas emissions by 45 per cent over the next decade, and to net zero emissions by 2050.

Read the Report of the Secretary-General on the outcomes of the Summit.

IPCC Climate Report 2022

The Working Group III report provides an updated global assessment of climate change mitigation progress and pledges, and examines the sources of global emissions. It explains developments in emission reduction and mitigation efforts, assessing the impact of national climate pledges in relation to long-term emissions goals.

Read more here

The Paris Agreement on climate change

The UN continues to encourage all stakeholders to take action toward reducing the impacts of climate change.

COP27: Egypt, 2022

From 6 to 18 November, Heads of State, ministers and negotiators, along with climate activists, mayors, civil society representatives and CEOs will meet in the Egyptian coastal city of Sharm el-Sheikh for the largest annual gathering on climate action.

The 27th Conference of the Parties to the United Nations Framework Convention on Climate Change –  COP27  – will build on the outcomes of  COP26  to deliver action on an array of issues critical to tackling the climate emergency – from urgently reducing greenhouse gas emissions, building resilience and adapting to the inevitable impacts of climate change, to delivering on the commitments to finance climate action in developing countries.

COP26: Glasgow, 2021

The UN Climate Change Conference in Glasgow (COP26) brought together 120 world leaders and over 40,000 registered participants, including 22,274 party delegates, 14.124 observers and 3.886 media representatives. For two weeks, the world was riveted on all facets of climate change — the science, the solutions, the political will to act, and clear indications of action.

The outcome of COP26 – the  Glasgow Climate Pact  – is the fruit of intense negotiations among almost 200 countries over the two weeks, strenuous formal and informal work over many months, and constant engagement both in-person and virtually for nearly two years.

COP25: Madrid, 2019

The Madrid Climate Change Conference – COP25 – brought the world together to consider ways to strengthen the implementation of the Paris Agreement. Taking place from 2 to 16 December in Madrid, the Conference came at a time when new data shows the climate emergency is getting worse every day, and is impacting people’s lives everywhere, whether from extreme heat, air pollution, wildfires, intensified flooding or droughts. Read our blogs from the Conference here .

COP24: Katowice, 2018

At the end of COP24, countries stressed “the urgency of enhanced ambition in order to ensure the highest possible mitigation and adaptation efforts by all Parties,” and agreed on a set of guidelines for implementing the landmark 2015 Paris Climate Change Agreement.

COP23: Bonn, 2017

The 2017 UN Climate Conference took place in Bonn, Germany, from 6-18 November. Leaders of national governments, cities, states, business, investors, NGOs and civil society gathered to speed up climate action to meet the goals of the Paris Climate Change Agreement.

COP22: Marrakesh, 2016

High-Level Event Towards Entry into Force: 21 September, 2016

Recap of the High-Level Event Towards Entry into Force

Paris Agreement Signing Ceremony, 22 April 2016

To keep the global spotlight focused on climate change and build on the strong political momentum from Paris, United Nations Secretary-General Ban Ki-moon invited representatives of all countries to sign  the Paris Agreement on climate change   at a special Ceremony at the United Nations Headquarters on 22 April.

COP21, 12 December 2015

The Paris Agreement was adopted by all 196 Parties to the  United Nations Framework Convention on Climate Change  at  COP21 in Paris  on 12 December 2015. In the agreement, all countries agreed to work to limit global temperature rise to well below 2 degrees Celsius, and given the grave risks, to strive for 1.5 degrees Celsius. Implementation of the Paris Agreement is essential for the achievement of the  Sustainable Development Goals , and provides a roadmap for climate actions that will reduce emissions and build climate resilience.

Paris Agreement – Frequently Asked Questions

What is the present status of the paris agreement on climate change.

The Paris Agreement on climate change officially entered into force on 4 November 2016, after 55 countries accounting for 55 per cent of the total global greenhouse gas emissions, deposited their instruments of ratification, acceptance or approval with the UN Secretary-General.

As of 28 September 2017, 166 countries have joined the Paris Agreement.

What is the next step towards the implementation of the Paris Agreement?

What are the most significant aspects about the new agreement.

The agreement provides a pathway forward to limit temperature rise to well below 2 degrees, maybe even 1.5. The agreement provides a mechanism to increase the level of ambition.

The Paris Agreement is an ambitious, dynamic and universal agreement. It covers all countries and all emissions, and is designed to last. This is a monumental agreement. It solidifies international cooperation for climate change. It provides a way forward.

The Paris Agreement sends a powerful signal to markets that now is the time to invest in the low emission economy. It contains a transparency framework to build mutual trust and confidence.

It will serve as an important tool in mobilizing finance technological support and capacity building for developing countries. And it will also help to scale up global efforts to address and minimize loss and damage from climate change.

Paris is a beginning—we now have to implement the Agreement. But we have taken a giant step forward.

Is this agreement really going to help?

The agreement is ambitious and it provides all the tools we need to address climate change, for reducing emissions and to adapt to the impacts of climate change.

The proof will be in the implementation, by governments, businesses and civil society.

What does the agreement require countries to do?

Countries officially submitted their own nationally determined climate actions. They have an obligation to implement these plans, and if they do, it will bend the curve downward in the projected global temperature rise.

The agreement not only formalizes the process of developing national plans, but also it provides a binding requirement to assess and review progress on these plans. This mechanism will require countries to continuously upgrade their commitments and ensure that there will be no backtracking.

This agreement is a clarion call from governments that they are ready for implementing the 2030 Sustainable Development Agenda.

What happens if a country doesn’t live up to its commitments? Would there be any enforcement?

There is no benefit to flouting the Agreement. Any short-term time gain will be short-lived. It will undoubtedly be overshadowed by negative reactions, by other countries, financial markets, and most important, by their citizens.

Developing countries stressed the need for equity and fairness. Does the Agreement provide that?

How can paris get us to the 2 degree—or even 1.5 degree goal.

We have an agreement and we have a chance now to reach our goal. We couldn’t say that without an agreement. The Paris Agreement will put us on a pathway to achieve the 2 degree goal or less. We did not expect to leave Paris with commitments to reach that goal, but rather, with a process that will get us there. And that is what the Agreement provides.

How are climate change and the Paris Agreement linked with the Sustainable Development Goals?

The Paris Conference featured thousands of climate action announcements that demonstrated how civil society and the private sector are moving forward to address climate change.

Why is it so urgent that we do something now?

We can limit global temperature rise to less than 2 degrees if we take action now. We need all countries and all sectors of society to act now—it is in the interests of everyone.

It is doable. Taking climate action now makes good economic sense. The more we delay, the more we pay. We can promote economic growth, eradicate extreme poverty, and improve people’s health and well-being by acting today.

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Essay on Global Warming

• Updated on  
• Apr 27, 2024

Being able to write an essay is an integral part of mastering any language. Essays form an integral part of many academic and scholastic exams like the SAT , and UPSC amongst many others. It is a crucial evaluative part of English proficiency tests as well like IELTS , TOEFL , etc. Major essays are meant to emphasize public issues of concern that can have significant consequences on the world. To understand the concept of Global Warming and its causes and effects, we must first examine the many factors that influence the planet’s temperature and what this implies for the world’s future. Here’s an unbiased look at the essay on Global Warming and other essential related topics.

Short Essay on Global Warming and Climate Change?

Since the industrial and scientific revolutions, Earth’s resources have been gradually depleted. Furthermore, the start of the world’s population’s exponential expansion is particularly hard on the environment. Simply put, as the population’s need for consumption grows, so does the use of natural resources , as well as the waste generated by that consumption.

Climate change has been one of the most significant long-term consequences of this. Climate change is more than just the rise or fall of global temperatures; it also affects rain cycles, wind patterns, cyclone frequencies, sea levels, and other factors. It has an impact on all major life groupings on the planet.

Also Read: World Population Day

What is Global Warming?

Global warming is the unusually rapid increase in Earth’s average surface temperature over the past century, primarily due to the greenhouse gases released by people burning fossil fuels . The greenhouse gases consist of methane, nitrous oxide, ozone, carbon dioxide, water vapour, and chlorofluorocarbons. The weather prediction has been becoming more complex with every passing year, with seasons more indistinguishable, and the general temperatures hotter.

The number of hurricanes, cyclones, droughts, floods, etc., has risen steadily since the onset of the 21st century. The supervillain behind all these changes is Global Warming. The name is quite self-explanatory; it means the rise in the temperature of the Earth.

Also Read: What is a Natural Disaster?

What are the Causes of Global Warming?

According to recent studies, many scientists believe the following are the primary four causes of global warming:

• Deforestation 
• Greenhouse emissions
• Carbon emissions per capita

Extreme global warming is causing natural disasters , which can be seen all around us. One of the causes of global warming is the extreme release of greenhouse gases that become trapped on the earth’s surface, causing the temperature to rise. Similarly, volcanoes contribute to global warming by spewing excessive CO2 into the atmosphere.

The increase in population is one of the major causes of Global Warming. This increase in population also leads to increased air pollution . Automobiles emit a lot of CO2, which remains in the atmosphere. This increase in population is also causing deforestation, which contributes to global warming.

The earth’s surface emits energy into the atmosphere in the form of heat, keeping the balance with the incoming energy. Global warming depletes the ozone layer, bringing about the end of the world. There is a clear indication that increased global warming will result in the extinction of all life on Earth’s surface.

Also Read: Land, Soil, Water, Natural Vegetation, and Wildlife Resources

Solutions for Global Warming

Of course, industries and multinational conglomerates emit more carbon than the average citizen. Nonetheless, activism and community effort are the only viable ways to slow the worsening effects of global warming. Furthermore, at the state or government level, world leaders must develop concrete plans and step-by-step programmes to ensure that no further harm is done to the environment in general.

Although we are almost too late to slow the rate of global warming, finding the right solution is critical. Everyone, from individuals to governments, must work together to find a solution to Global Warming. Some of the factors to consider are pollution control, population growth, and the use of natural resources.

One very important contribution you can make is to reduce your use of plastic. Plastic is the primary cause of global warming, and recycling it takes years. Another factor to consider is deforestation, which will aid in the control of global warming. More tree planting should be encouraged to green the environment. Certain rules should also govern industrialization. Building industries in green zones that affect plants and species should be prohibited.

Also Read: Essay on Pollution

Effects of Global Warming

Global warming is a real problem that many people want to disprove to gain political advantage. However, as global citizens, we must ensure that only the truth is presented in the media.

This decade has seen a significant impact from global warming. The two most common phenomena observed are glacier retreat and arctic shrinkage. Glaciers are rapidly melting. These are clear manifestations of climate change.

Another significant effect of global warming is the rise in sea level. Flooding is occurring in low-lying areas as a result of sea-level rise. Many countries have experienced extreme weather conditions. Every year, we have unusually heavy rain, extreme heat and cold, wildfires, and other natural disasters.

Similarly, as global warming continues, marine life is being severely impacted. This is causing the extinction of marine species as well as other problems. Furthermore, changes are expected in coral reefs, which will face extinction in the coming years. These effects will intensify in the coming years, effectively halting species expansion. Furthermore, humans will eventually feel the negative effects of Global Warming.

Also Read: Concept of Sustainable Development

Sample Essays on Global Warming

Here are some sample essays on Global Warming:

Essay on Global Warming Paragraph in 100 – 150 words

Global Warming is caused by the increase of carbon dioxide levels in the earth’s atmosphere and is a result of human activities that have been causing harm to our environment for the past few centuries now. Global Warming is something that can’t be ignored and steps have to be taken to tackle the situation globally. The average temperature is constantly rising by 1.5 degrees Celsius over the last few years.

The best method to prevent future damage to the earth, cutting down more forests should be banned and Afforestation should be encouraged. Start by planting trees near your homes and offices, participate in events, and teach the importance of planting trees. It is impossible to undo the damage but it is possible to stop further harm.

Also Read: Social Forestry

Essay on Global Warming in 250 Words

Over a long period, it is observed that the temperature of the earth is increasing. This affected wildlife, animals, humans, and every living organism on earth. Glaciers have been melting, and many countries have started water shortages, flooding, and erosion and all this is because of global warming. 

No one can be blamed for global warming except for humans. Human activities such as gases released from power plants, transportation, and deforestation have increased gases such as carbon dioxide, CFCs, and other pollutants in the earth’s atmosphere.                                              The main question is how can we control the current situation and build a better world for future generations. It starts with little steps by every individual. 

Start using cloth bags made from sustainable materials for all shopping purposes, instead of using high-watt lights use energy-efficient bulbs, switch off the electricity, don’t waste water, abolish deforestation and encourage planting more trees. Shift the use of energy from petroleum or other fossil fuels to wind and solar energy. Instead of throwing out the old clothes donate them to someone so that it is recycled. 

Donate old books, don’t waste paper.  Above all, spread awareness about global warming. Every little thing a person does towards saving the earth will contribute in big or small amounts. We must learn that 1% effort is better than no effort. Pledge to take care of Mother Nature and speak up about global warming.

Also Read: Types of Water Pollution

Essay on Global Warming in 500 Words

Global warming isn’t a prediction, it is happening! A person denying it or unaware of it is in the most simple terms complicit. Do we have another planet to live on? Unfortunately, we have been bestowed with this one planet only that can sustain life yet over the years we have turned a blind eye to the plight it is in. Global warming is not an abstract concept but a global phenomenon occurring ever so slowly even at this moment. Global Warming is a phenomenon that is occurring every minute resulting in a gradual increase in the Earth’s overall climate. Brought about by greenhouse gases that trap the solar radiation in the atmosphere, global warming can change the entire map of the earth, displacing areas, flooding many countries, and destroying multiple lifeforms. Extreme weather is a direct consequence of global warming but it is not an exhaustive consequence. There are virtually limitless effects of global warming which are all harmful to life on earth. The sea level is increasing by 0.12 inches per year worldwide. This is happening because of the melting of polar ice caps because of global warming. This has increased the frequency of floods in many lowland areas and has caused damage to coral reefs. The Arctic is one of the worst-hit areas affected by global warming. Air quality has been adversely affected and the acidity of the seawater has also increased causing severe damage to marine life forms. Severe natural disasters are brought about by global warming which has had dire effects on life and property. As long as mankind produces greenhouse gases, global warming will continue to accelerate. The consequences are felt at a much smaller scale which will increase to become drastic shortly. The power to save the day lies in the hands of humans, the need is to seize the day. Energy consumption should be reduced on an individual basis. Fuel-efficient cars and other electronics should be encouraged to reduce the wastage of energy sources. This will also improve air quality and reduce the concentration of greenhouse gases in the atmosphere. Global warming is an evil that can only be defeated when fought together. It is better late than never. If we all take steps today, we will have a much brighter future tomorrow. Global warming is the bane of our existence and various policies have come up worldwide to fight it but that is not enough. The actual difference is made when we work at an individual level to fight it. Understanding its import now is crucial before it becomes an irrevocable mistake. Exterminating global warming is of utmost importance and each one of us is as responsible for it as the next.  

Also Read: Essay on Library: 100, 200 and 250 Words

Essay on Global Warming UPSC

Always hear about global warming everywhere, but do we know what it is? The evil of the worst form, global warming is a phenomenon that can affect life more fatally. Global warming refers to the increase in the earth’s temperature as a result of various human activities. The planet is gradually getting hotter and threatening the existence of lifeforms on it. Despite being relentlessly studied and researched, global warming for the majority of the population remains an abstract concept of science. It is this concept that over the years has culminated in making global warming a stark reality and not a concept covered in books. Global warming is not caused by one sole reason that can be curbed. Multifarious factors cause global warming most of which are a part of an individual’s daily existence. Burning of fuels for cooking, in vehicles, and for other conventional uses, a large amount of greenhouse gases like carbon dioxide, and methane amongst many others is produced which accelerates global warming. Rampant deforestation also results in global warming as lesser green cover results in an increased presence of carbon dioxide in the atmosphere which is a greenhouse gas.  Finding a solution to global warming is of immediate importance. Global warming is a phenomenon that has to be fought unitedly. Planting more trees can be the first step that can be taken toward warding off the severe consequences of global warming. Increasing the green cover will result in regulating the carbon cycle. There should be a shift from using nonrenewable energy to renewable energy such as wind or solar energy which causes less pollution and thereby hinder the acceleration of global warming. Reducing energy needs at an individual level and not wasting energy in any form is the most important step to be taken against global warming. The warning bells are tolling to awaken us from the deep slumber of complacency we have slipped into. Humans can fight against nature and it is high time we acknowledged that. With all our scientific progress and technological inventions, fighting off the negative effects of global warming is implausible. We have to remember that we do not inherit the earth from our ancestors but borrow it from our future generations and the responsibility lies on our shoulders to bequeath them a healthy planet for life to exist. 

Also Read: Essay on Disaster Management

Climate Change and Global Warming Essay

Global Warming and Climate Change are two sides of the same coin. Both are interrelated with each other and are two issues of major concern worldwide. Greenhouse gases released such as carbon dioxide, CFCs, and other pollutants in the earth’s atmosphere cause Global Warming which leads to climate change. Black holes have started to form in the ozone layer that protects the earth from harmful ultraviolet rays. 

Human activities have created climate change and global warming. Industrial waste and fumes are the major contributors to global warming. 

Another factor affecting is the burning of fossil fuels, deforestation and also one of the reasons for climate change.  Global warming has resulted in shrinking mountain glaciers in Antarctica, Greenland, and the Arctic and causing climate change. Switching from the use of fossil fuels to energy sources like wind and solar. 

When buying any electronic appliance buy the best quality with energy savings stars. Don’t waste water and encourage rainwater harvesting in your community. 

Also Read: Essay on Air Pollution

Tips to Write an Essay

Writing an effective essay needs skills that few people possess and even fewer know how to implement. While writing an essay can be an assiduous task that can be unnerving at times, some key pointers can be inculcated to draft a successful essay. These involve focusing on the structure of the essay, planning it out well, and emphasizing crucial details.

Mentioned below are some pointers that can help you write better structure and more thoughtful essays that will get across to your readers:

• Prepare an outline for the essay to ensure continuity and relevance and no break in the structure of the essay
• Decide on a thesis statement that will form the basis of your essay. It will be the point of your essay and help readers understand your contention
• Follow the structure of an introduction, a detailed body followed by a conclusion so that the readers can comprehend the essay in a particular manner without any dissonance.
• Make your beginning catchy and include solutions in your conclusion to make the essay insightful and lucrative to read
• Reread before putting it out and add your flair to the essay to make it more personal and thereby unique and intriguing for readers  

Also Read: I Love My India Essay: 100 and 500+ Words in English for School Students

Ans. Both natural and man-made factors contribute to global warming. The natural one also contains methane gas, volcanic eruptions, and greenhouse gases. Deforestation, mining, livestock raising, burning fossil fuels, and other man-made causes are next.

Ans. The government and the general public can work together to stop global warming. Trees must be planted more often, and deforestation must be prohibited. Auto usage needs to be curbed, and recycling needs to be promoted.

Ans. Switching to renewable energy sources , adopting sustainable farming, transportation, and energy methods, and conserving water and other natural resources.

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Digvijay Singh

Having 2+ years of experience in educational content writing, withholding a Bachelor's in Physical Education and Sports Science and a strong interest in writing educational content for students enrolled in domestic and foreign study abroad programmes. I believe in offering a distinct viewpoint to the table, to help students deal with the complexities of both domestic and foreign educational systems. Through engaging storytelling and insightful analysis, I aim to inspire my readers to embark on their educational journeys, whether abroad or at home, and to make the most of every learning opportunity that comes their way.

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This was really a good essay on global warming… There has been used many unic words..and I really liked it!!!Seriously I had been looking for a essay about Global warming just like this…

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I want to learn how to write essay writing so I joined this page.This page is very useful for everyone.

Hi, we are glad that we could help you to write essays. We have a beginner’s guide to write essays ( https://leverageedu.com/blog/essay-writing/ ) and we think this might help you.

It is not good , to have global warming in our earth .So we all have to afforestation program on all the world.

thank you so much

Very educative , helpful and it is really going to strength my English knowledge to structure my essay in future

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Global warming is the increase in 𝓽𝓱𝓮 ᴀᴠᴇʀᴀɢᴇ ᴛᴇᴍᴘᴇʀᴀᴛᴜʀᴇs ᴏғ ᴇᴀʀᴛʜ🌎 ᴀᴛᴍᴏsᴘʜᴇʀᴇ

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The Science of Climate Change Explained: Facts, Evidence and Proof

Definitive answers to the big questions.

Credit... Photo Illustration by Andrea D'Aquino

Supported by

By Julia Rosen

Ms. Rosen is a journalist with a Ph.D. in geology. Her research involved studying ice cores from Greenland and Antarctica to understand past climate changes.

• Published April 19, 2021 Updated Nov. 6, 2021

The science of climate change is more solid and widely agreed upon than you might think. But the scope of the topic, as well as rampant disinformation, can make it hard to separate fact from fiction. Here, we’ve done our best to present you with not only the most accurate scientific information, but also an explanation of how we know it.

How do we know climate change is really happening?

How much agreement is there among scientists about climate change, do we really only have 150 years of climate data how is that enough to tell us about centuries of change, how do we know climate change is caused by humans, since greenhouse gases occur naturally, how do we know they’re causing earth’s temperature to rise, why should we be worried that the planet has warmed 2°f since the 1800s, is climate change a part of the planet’s natural warming and cooling cycles, how do we know global warming is not because of the sun or volcanoes, how can winters and certain places be getting colder if the planet is warming, wildfires and bad weather have always happened. how do we know there’s a connection to climate change, how bad are the effects of climate change going to be, what will it cost to do something about climate change, versus doing nothing.

Climate change is often cast as a prediction made by complicated computer models. But the scientific basis for climate change is much broader, and models are actually only one part of it (and, for what it’s worth, they’re surprisingly accurate ).

For more than a century , scientists have understood the basic physics behind why greenhouse gases like carbon dioxide cause warming. These gases make up just a small fraction of the atmosphere but exert outsized control on Earth’s climate by trapping some of the planet’s heat before it escapes into space. This greenhouse effect is important: It’s why a planet so far from the sun has liquid water and life!

However, during the Industrial Revolution, people started burning coal and other fossil fuels to power factories, smelters and steam engines, which added more greenhouse gases to the atmosphere. Ever since, human activities have been heating the planet.

We know this is true thanks to an overwhelming body of evidence that begins with temperature measurements taken at weather stations and on ships starting in the mid-1800s. Later, scientists began tracking surface temperatures with satellites and looking for clues about climate change in geologic records. Together, these data all tell the same story: Earth is getting hotter.

Average global temperatures have increased by 2.2 degrees Fahrenheit, or 1.2 degrees Celsius, since 1880, with the greatest changes happening in the late 20th century. Land areas have warmed more than the sea surface and the Arctic has warmed the most — by more than 4 degrees Fahrenheit just since the 1960s. Temperature extremes have also shifted. In the United States, daily record highs now outnumber record lows two-to-one.

Where it was cooler or warmer in 2020 compared with the middle of the 20th century

This warming is unprecedented in recent geologic history. A famous illustration, first published in 1998 and often called the hockey-stick graph, shows how temperatures remained fairly flat for centuries (the shaft of the stick) before turning sharply upward (the blade). It’s based on data from tree rings, ice cores and other natural indicators. And the basic picture , which has withstood decades of scrutiny from climate scientists and contrarians alike, shows that Earth is hotter today than it’s been in at least 1,000 years, and probably much longer.

In fact, surface temperatures actually mask the true scale of climate change, because the ocean has absorbed 90 percent of the heat trapped by greenhouse gases . Measurements collected over the last six decades by oceanographic expeditions and networks of floating instruments show that every layer of the ocean is warming up. According to one study , the ocean has absorbed as much heat between 1997 and 2015 as it did in the previous 130 years.

We also know that climate change is happening because we see the effects everywhere. Ice sheets and glaciers are shrinking while sea levels are rising. Arctic sea ice is disappearing. In the spring, snow melts sooner and plants flower earlier. Animals are moving to higher elevations and latitudes to find cooler conditions. And droughts, floods and wildfires have all gotten more extreme. Models predicted many of these changes, but observations show they are now coming to pass.

Back to top .

There’s no denying that scientists love a good, old-fashioned argument. But when it comes to climate change, there is virtually no debate: Numerous studies have found that more than 90 percent of scientists who study Earth’s climate agree that the planet is warming and that humans are the primary cause. Most major scientific bodies, from NASA to the World Meteorological Organization , endorse this view. That’s an astounding level of consensus given the contrarian, competitive nature of the scientific enterprise, where questions like what killed the dinosaurs remain bitterly contested .

Scientific agreement about climate change started to emerge in the late 1980s, when the influence of human-caused warming began to rise above natural climate variability. By 1991, two-thirds of earth and atmospheric scientists surveyed for an early consensus study said that they accepted the idea of anthropogenic global warming. And by 1995, the Intergovernmental Panel on Climate Change, a famously conservative body that periodically takes stock of the state of scientific knowledge, concluded that “the balance of evidence suggests that there is a discernible human influence on global climate.” Currently, more than 97 percent of publishing climate scientists agree on the existence and cause of climate change (as does nearly 60 percent of the general population of the United States).

So where did we get the idea that there’s still debate about climate change? A lot of it came from coordinated messaging campaigns by companies and politicians that opposed climate action. Many pushed the narrative that scientists still hadn’t made up their minds about climate change, even though that was misleading. Frank Luntz, a Republican consultant, explained the rationale in an infamous 2002 memo to conservative lawmakers: “Should the public come to believe that the scientific issues are settled, their views about global warming will change accordingly,” he wrote. Questioning consensus remains a common talking point today, and the 97 percent figure has become something of a lightning rod .

To bolster the falsehood of lingering scientific doubt, some people have pointed to things like the Global Warming Petition Project, which urged the United States government to reject the Kyoto Protocol of 1997, an early international climate agreement. The petition proclaimed that climate change wasn’t happening, and even if it were, it wouldn’t be bad for humanity. Since 1998, more than 30,000 people with science degrees have signed it. However, nearly 90 percent of them studied something other than Earth, atmospheric or environmental science, and the signatories included just 39 climatologists. Most were engineers, doctors, and others whose training had little to do with the physics of the climate system.

A few well-known researchers remain opposed to the scientific consensus. Some, like Willie Soon, a researcher affiliated with the Harvard-Smithsonian Center for Astrophysics, have ties to the fossil fuel industry . Others do not, but their assertions have not held up under the weight of evidence. At least one prominent skeptic, the physicist Richard Muller, changed his mind after reassessing historical temperature data as part of the Berkeley Earth project. His team’s findings essentially confirmed the results he had set out to investigate, and he came away firmly convinced that human activities were warming the planet. “Call me a converted skeptic,” he wrote in an Op-Ed for the Times in 2012.

Mr. Luntz, the Republican pollster, has also reversed his position on climate change and now advises politicians on how to motivate climate action.

A final note on uncertainty: Denialists often use it as evidence that climate science isn’t settled. However, in science, uncertainty doesn’t imply a lack of knowledge. Rather, it’s a measure of how well something is known. In the case of climate change, scientists have found a range of possible future changes in temperature, precipitation and other important variables — which will depend largely on how quickly we reduce emissions. But uncertainty does not undermine their confidence that climate change is real and that people are causing it.

Earth’s climate is inherently variable. Some years are hot and others are cold, some decades bring more hurricanes than others, some ancient droughts spanned the better part of centuries. Glacial cycles operate over many millenniums. So how can scientists look at data collected over a relatively short period of time and conclude that humans are warming the planet? The answer is that the instrumental temperature data that we have tells us a lot, but it’s not all we have to go on.

Historical records stretch back to the 1880s (and often before), when people began to regularly measure temperatures at weather stations and on ships as they traversed the world’s oceans. These data show a clear warming trend during the 20th century.

Global average temperature compared with the middle of the 20th century

+0.75°C

–0.25°

Some have questioned whether these records could be skewed, for instance, by the fact that a disproportionate number of weather stations are near cities, which tend to be hotter than surrounding areas as a result of the so-called urban heat island effect. However, researchers regularly correct for these potential biases when reconstructing global temperatures. In addition, warming is corroborated by independent data like satellite observations, which cover the whole planet, and other ways of measuring temperature changes.

Much has also been made of the small dips and pauses that punctuate the rising temperature trend of the last 150 years. But these are just the result of natural climate variability or other human activities that temporarily counteract greenhouse warming. For instance, in the mid-1900s, internal climate dynamics and light-blocking pollution from coal-fired power plants halted global warming for a few decades. (Eventually, rising greenhouse gases and pollution-control laws caused the planet to start heating up again.) Likewise, the so-called warming hiatus of the 2000s was partly a result of natural climate variability that allowed more heat to enter the ocean rather than warm the atmosphere. The years since have been the hottest on record .

Still, could the entire 20th century just be one big natural climate wiggle? To address that question, we can look at other kinds of data that give a longer perspective. Researchers have used geologic records like tree rings, ice cores, corals and sediments that preserve information about prehistoric climates to extend the climate record. The resulting picture of global temperature change is basically flat for centuries, then turns sharply upward over the last 150 years. It has been a target of climate denialists for decades. However, study after study has confirmed the results , which show that the planet hasn’t been this hot in at least 1,000 years, and probably longer.

Scientists have studied past climate changes to understand the factors that can cause the planet to warm or cool. The big ones are changes in solar energy, ocean circulation, volcanic activity and the amount of greenhouse gases in the atmosphere. And they have each played a role at times.

For example, 300 years ago, a combination of reduced solar output and increased volcanic activity cooled parts of the planet enough that Londoners regularly ice skated on the Thames . About 12,000 years ago, major changes in Atlantic circulation plunged the Northern Hemisphere into a frigid state. And 56 million years ago, a giant burst of greenhouse gases, from volcanic activity or vast deposits of methane (or both), abruptly warmed the planet by at least 9 degrees Fahrenheit, scrambling the climate, choking the oceans and triggering mass extinctions.

In trying to determine the cause of current climate changes, scientists have looked at all of these factors . The first three have varied a bit over the last few centuries and they have quite likely had modest effects on climate , particularly before 1950. But they cannot account for the planet’s rapidly rising temperature, especially in the second half of the 20th century, when solar output actually declined and volcanic eruptions exerted a cooling effect.

That warming is best explained by rising greenhouse gas concentrations . Greenhouse gases have a powerful effect on climate (see the next question for why). And since the Industrial Revolution, humans have been adding more of them to the atmosphere, primarily by extracting and burning fossil fuels like coal, oil and gas, which releases carbon dioxide.

Bubbles of ancient air trapped in ice show that, before about 1750, the concentration of carbon dioxide in the atmosphere was roughly 280 parts per million. It began to rise slowly and crossed the 300 p.p.m. threshold around 1900. CO2 levels then accelerated as cars and electricity became big parts of modern life, recently topping 420 p.p.m . The concentration of methane, the second most important greenhouse gas, has more than doubled. We’re now emitting carbon much faster than it was released 56 million years ago .

30 billion metric tons

Carbon dioxide emitted worldwide 1850-2017

Rest of world

Other developed

European Union

Developed economies

Other countries

United States

E.U. and U.K.

These rapid increases in greenhouse gases have caused the climate to warm abruptly. In fact, climate models suggest that greenhouse warming can explain virtually all of the temperature change since 1950. According to the most recent report by the Intergovernmental Panel on Climate Change, which assesses published scientific literature, natural drivers and internal climate variability can only explain a small fraction of late-20th century warming.

Another study put it this way: The odds of current warming occurring without anthropogenic greenhouse gas emissions are less than 1 in 100,000 .

But greenhouse gases aren’t the only climate-altering compounds people put into the air. Burning fossil fuels also produces particulate pollution that reflects sunlight and cools the planet. Scientists estimate that this pollution has masked up to half of the greenhouse warming we would have otherwise experienced.

Greenhouse gases like water vapor and carbon dioxide serve an important role in the climate. Without them, Earth would be far too cold to maintain liquid water and humans would not exist!

Here’s how it works: the planet’s temperature is basically a function of the energy the Earth absorbs from the sun (which heats it up) and the energy Earth emits to space as infrared radiation (which cools it down). Because of their molecular structure, greenhouse gases temporarily absorb some of that outgoing infrared radiation and then re-emit it in all directions, sending some of that energy back toward the surface and heating the planet . Scientists have understood this process since the 1850s .

Greenhouse gas concentrations have varied naturally in the past. Over millions of years, atmospheric CO2 levels have changed depending on how much of the gas volcanoes belched into the air and how much got removed through geologic processes. On time scales of hundreds to thousands of years, concentrations have changed as carbon has cycled between the ocean, soil and air.

Today, however, we are the ones causing CO2 levels to increase at an unprecedented pace by taking ancient carbon from geologic deposits of fossil fuels and putting it into the atmosphere when we burn them. Since 1750, carbon dioxide concentrations have increased by almost 50 percent. Methane and nitrous oxide, other important anthropogenic greenhouse gases that are released mainly by agricultural activities, have also spiked over the last 250 years.

We know based on the physics described above that this should cause the climate to warm. We also see certain telltale “fingerprints” of greenhouse warming. For example, nights are warming even faster than days because greenhouse gases don’t go away when the sun sets. And upper layers of the atmosphere have actually cooled, because more energy is being trapped by greenhouse gases in the lower atmosphere.

We also know that we are the cause of rising greenhouse gas concentrations — and not just because we can measure the CO2 coming out of tailpipes and smokestacks. We can see it in the chemical signature of the carbon in CO2.

Carbon comes in three different masses: 12, 13 and 14. Things made of organic matter (including fossil fuels) tend to have relatively less carbon-13. Volcanoes tend to produce CO2 with relatively more carbon-13. And over the last century, the carbon in atmospheric CO2 has gotten lighter, pointing to an organic source.

We can tell it’s old organic matter by looking for carbon-14, which is radioactive and decays over time. Fossil fuels are too ancient to have any carbon-14 left in them, so if they were behind rising CO2 levels, you would expect the amount of carbon-14 in the atmosphere to drop, which is exactly what the data show .

It’s important to note that water vapor is the most abundant greenhouse gas in the atmosphere. However, it does not cause warming; instead it responds to it . That’s because warmer air holds more moisture, which creates a snowball effect in which human-caused warming allows the atmosphere to hold more water vapor and further amplifies climate change. This so-called feedback cycle has doubled the warming caused by anthropogenic greenhouse gas emissions.

A common source of confusion when it comes to climate change is the difference between weather and climate. Weather is the constantly changing set of meteorological conditions that we experience when we step outside, whereas climate is the long-term average of those conditions, usually calculated over a 30-year period. Or, as some say: Weather is your mood and climate is your personality.

So while 2 degrees Fahrenheit doesn’t represent a big change in the weather, it’s a huge change in climate. As we’ve already seen, it’s enough to melt ice and raise sea levels, to shift rainfall patterns around the world and to reorganize ecosystems, sending animals scurrying toward cooler habitats and killing trees by the millions.

It’s also important to remember that two degrees represents the global average, and many parts of the world have already warmed by more than that. For example, land areas have warmed about twice as much as the sea surface. And the Arctic has warmed by about 5 degrees. That’s because the loss of snow and ice at high latitudes allows the ground to absorb more energy, causing additional heating on top of greenhouse warming.

Relatively small long-term changes in climate averages also shift extremes in significant ways. For instance, heat waves have always happened, but they have shattered records in recent years. In June of 2020, a town in Siberia registered temperatures of 100 degrees . And in Australia, meteorologists have added a new color to their weather maps to show areas where temperatures exceed 125 degrees. Rising sea levels have also increased the risk of flooding because of storm surges and high tides. These are the foreshocks of climate change.

And we are in for more changes in the future — up to 9 degrees Fahrenheit of average global warming by the end of the century, in the worst-case scenario . For reference, the difference in global average temperatures between now and the peak of the last ice age, when ice sheets covered large parts of North America and Europe, is about 11 degrees Fahrenheit.

Under the Paris Climate Agreement, which President Biden recently rejoined, countries have agreed to try to limit total warming to between 1.5 and 2 degrees Celsius, or 2.7 and 3.6 degrees Fahrenheit, since preindustrial times. And even this narrow range has huge implications . According to scientific studies, the difference between 2.7 and 3.6 degrees Fahrenheit will very likely mean the difference between coral reefs hanging on or going extinct, and between summer sea ice persisting in the Arctic or disappearing completely. It will also determine how many millions of people suffer from water scarcity and crop failures, and how many are driven from their homes by rising seas. In other words, one degree Fahrenheit makes a world of difference.

Earth’s climate has always changed. Hundreds of millions of years ago, the entire planet froze . Fifty million years ago, alligators lived in what we now call the Arctic . And for the last 2.6 million years, the planet has cycled between ice ages when the planet was up to 11 degrees cooler and ice sheets covered much of North America and Europe, and milder interglacial periods like the one we’re in now.

Climate denialists often point to these natural climate changes as a way to cast doubt on the idea that humans are causing climate to change today. However, that argument rests on a logical fallacy. It’s like “seeing a murdered body and concluding that people have died of natural causes in the past, so the murder victim must also have died of natural causes,” a team of social scientists wrote in The Debunking Handbook , which explains the misinformation strategies behind many climate myths.

Indeed, we know that different mechanisms caused the climate to change in the past. Glacial cycles, for example, were triggered by periodic variations in Earth’s orbit , which take place over tens of thousands of years and change how solar energy gets distributed around the globe and across the seasons.

These orbital variations don’t affect the planet’s temperature much on their own. But they set off a cascade of other changes in the climate system; for instance, growing or melting vast Northern Hemisphere ice sheets and altering ocean circulation. These changes, in turn, affect climate by altering the amount of snow and ice, which reflect sunlight, and by changing greenhouse gas concentrations. This is actually part of how we know that greenhouse gases have the ability to significantly affect Earth’s temperature.

For at least the last 800,000 years , atmospheric CO2 concentrations oscillated between about 180 parts per million during ice ages and about 280 p.p.m. during warmer periods, as carbon moved between oceans, forests, soils and the atmosphere. These changes occurred in lock step with global temperatures, and are a major reason the entire planet warmed and cooled during glacial cycles, not just the frozen poles.

Today, however, CO2 levels have soared to 420 p.p.m. — the highest they’ve been in at least three million years . The concentration of CO2 is also increasing about 100 times faster than it did at the end of the last ice age. This suggests something else is going on, and we know what it is: Since the Industrial Revolution, humans have been burning fossil fuels and releasing greenhouse gases that are heating the planet now (see Question 5 for more details on how we know this, and Questions 4 and 8 for how we know that other natural forces aren’t to blame).

Over the next century or two, societies and ecosystems will experience the consequences of this climate change. But our emissions will have even more lasting geologic impacts: According to some studies, greenhouse gas levels may have already warmed the planet enough to delay the onset of the next glacial cycle for at least an additional 50,000 years.

The sun is the ultimate source of energy in Earth’s climate system, so it’s a natural candidate for causing climate change. And solar activity has certainly changed over time. We know from satellite measurements and other astronomical observations that the sun’s output changes on 11-year cycles. Geologic records and sunspot numbers, which astronomers have tracked for centuries, also show long-term variations in the sun’s activity, including some exceptionally quiet periods in the late 1600s and early 1800s.

We know that, from 1900 until the 1950s, solar irradiance increased. And studies suggest that this had a modest effect on early 20th century climate, explaining up to 10 percent of the warming that’s occurred since the late 1800s. However, in the second half of the century, when the most warming occurred, solar activity actually declined . This disparity is one of the main reasons we know that the sun is not the driving force behind climate change.

Another reason we know that solar activity hasn’t caused recent warming is that, if it had, all the layers of the atmosphere should be heating up. Instead, data show that the upper atmosphere has actually cooled in recent decades — a hallmark of greenhouse warming .

So how about volcanoes? Eruptions cool the planet by injecting ash and aerosol particles into the atmosphere that reflect sunlight. We’ve observed this effect in the years following large eruptions. There are also some notable historical examples, like when Iceland’s Laki volcano erupted in 1783, causing widespread crop failures in Europe and beyond, and the “ year without a summer ,” which followed the 1815 eruption of Mount Tambora in Indonesia.

Since volcanoes mainly act as climate coolers, they can’t really explain recent warming. However, scientists say that they may also have contributed slightly to rising temperatures in the early 20th century. That’s because there were several large eruptions in the late 1800s that cooled the planet, followed by a few decades with no major volcanic events when warming caught up. During the second half of the 20th century, though, several big eruptions occurred as the planet was heating up fast. If anything, they temporarily masked some amount of human-caused warming.

The second way volcanoes can impact climate is by emitting carbon dioxide. This is important on time scales of millions of years — it’s what keeps the planet habitable (see Question 5 for more on the greenhouse effect). But by comparison to modern anthropogenic emissions, even big eruptions like Krakatoa and Mount St. Helens are just a drop in the bucket. After all, they last only a few hours or days, while we burn fossil fuels 24-7. Studies suggest that, today, volcanoes account for 1 to 2 percent of total CO2 emissions.

When a big snowstorm hits the United States, climate denialists can try to cite it as proof that climate change isn’t happening. In 2015, Senator James Inhofe, an Oklahoma Republican, famously lobbed a snowball in the Senate as he denounced climate science. But these events don’t actually disprove climate change.

While there have been some memorable storms in recent years, winters are actually warming across the world. In the United States, average temperatures in December, January and February have increased by about 2.5 degrees this century.

On the flip side, record cold days are becoming less common than record warm days. In the United States, record highs now outnumber record lows two-to-one . And ever-smaller areas of the country experience extremely cold winter temperatures . (The same trends are happening globally.)

So what’s with the blizzards? Weather always varies, so it’s no surprise that we still have severe winter storms even as average temperatures rise. However, some studies suggest that climate change may be to blame. One possibility is that rapid Arctic warming has affected atmospheric circulation, including the fast-flowing, high-altitude air that usually swirls over the North Pole (a.k.a. the Polar Vortex ). Some studies suggest that these changes are bringing more frigid temperatures to lower latitudes and causing weather systems to stall , allowing storms to produce more snowfall. This may explain what we’ve experienced in the U.S. over the past few decades, as well as a wintertime cooling trend in Siberia , although exactly how the Arctic affects global weather remains a topic of ongoing scientific debate .

Climate change may also explain the apparent paradox behind some of the other places on Earth that haven’t warmed much. For instance, a splotch of water in the North Atlantic has cooled in recent years, and scientists say they suspect that may be because ocean circulation is slowing as a result of freshwater streaming off a melting Greenland . If this circulation grinds almost to a halt, as it’s done in the geologic past, it would alter weather patterns around the world.

Not all cold weather stems from some counterintuitive consequence of climate change. But it’s a good reminder that Earth’s climate system is complex and chaotic, so the effects of human-caused changes will play out differently in different places. That’s why “global warming” is a bit of an oversimplification. Instead, some scientists have suggested that the phenomenon of human-caused climate change would more aptly be called “ global weirding .”

Extreme weather and natural disasters are part of life on Earth — just ask the dinosaurs. But there is good evidence that climate change has increased the frequency and severity of certain phenomena like heat waves, droughts and floods. Recent research has also allowed scientists to identify the influence of climate change on specific events.

Let’s start with heat waves . Studies show that stretches of abnormally high temperatures now happen about five times more often than they would without climate change, and they last longer, too. Climate models project that, by the 2040s, heat waves will be about 12 times more frequent. And that’s concerning since extreme heat often causes increased hospitalizations and deaths, particularly among older people and those with underlying health conditions. In the summer of 2003, for example, a heat wave caused an estimated 70,000 excess deaths across Europe. (Human-caused warming amplified the death toll .)

Climate change has also exacerbated droughts , primarily by increasing evaporation. Droughts occur naturally because of random climate variability and factors like whether El Niño or La Niña conditions prevail in the tropical Pacific. But some researchers have found evidence that greenhouse warming has been affecting droughts since even before the Dust Bowl . And it continues to do so today. According to one analysis , the drought that afflicted the American Southwest from 2000 to 2018 was almost 50 percent more severe because of climate change. It was the worst drought the region had experienced in more than 1,000 years.

Rising temperatures have also increased the intensity of heavy precipitation events and the flooding that often follows. For example, studies have found that, because warmer air holds more moisture, Hurricane Harvey, which struck Houston in 2017, dropped between 15 and 40 percent more rainfall than it would have without climate change.

It’s still unclear whether climate change is changing the overall frequency of hurricanes, but it is making them stronger . And warming appears to favor certain kinds of weather patterns, like the “ Midwest Water Hose ” events that caused devastating flooding across the Midwest in 2019 .

It’s important to remember that in most natural disasters, there are multiple factors at play. For instance, the 2019 Midwest floods occurred after a recent cold snap had frozen the ground solid, preventing the soil from absorbing rainwater and increasing runoff into the Missouri and Mississippi Rivers. These waterways have also been reshaped by levees and other forms of river engineering, some of which failed in the floods.

Wildfires are another phenomenon with multiple causes. In many places, fire risk has increased because humans have aggressively fought natural fires and prevented Indigenous peoples from carrying out traditional burning practices. This has allowed fuel to accumulate that makes current fires worse .

However, climate change still plays a major role by heating and drying forests, turning them into tinderboxes. Studies show that warming is the driving factor behind the recent increases in wildfires; one analysis found that climate change is responsible for doubling the area burned across the American West between 1984 and 2015. And researchers say that warming will only make fires bigger and more dangerous in the future.

It depends on how aggressively we act to address climate change. If we continue with business as usual, by the end of the century, it will be too hot to go outside during heat waves in the Middle East and South Asia . Droughts will grip Central America, the Mediterranean and southern Africa. And many island nations and low-lying areas, from Texas to Bangladesh, will be overtaken by rising seas. Conversely, climate change could bring welcome warming and extended growing seasons to the upper Midwest , Canada, the Nordic countries and Russia . Farther north, however, the loss of snow, ice and permafrost will upend the traditions of Indigenous peoples and threaten infrastructure.

It’s complicated, but the underlying message is simple: unchecked climate change will likely exacerbate existing inequalities . At a national level, poorer countries will be hit hardest, even though they have historically emitted only a fraction of the greenhouse gases that cause warming. That’s because many less developed countries tend to be in tropical regions where additional warming will make the climate increasingly intolerable for humans and crops. These nations also often have greater vulnerabilities, like large coastal populations and people living in improvised housing that is easily damaged in storms. And they have fewer resources to adapt, which will require expensive measures like redesigning cities, engineering coastlines and changing how people grow food.

Already, between 1961 and 2000, climate change appears to have harmed the economies of the poorest countries while boosting the fortunes of the wealthiest nations that have done the most to cause the problem, making the global wealth gap 25 percent bigger than it would otherwise have been. Similarly, the Global Climate Risk Index found that lower income countries — like Myanmar, Haiti and Nepal — rank high on the list of nations most affected by extreme weather between 1999 and 2018. Climate change has also contributed to increased human migration, which is expected to increase significantly .

Even within wealthy countries, the poor and marginalized will suffer the most. People with more resources have greater buffers, like air-conditioners to keep their houses cool during dangerous heat waves, and the means to pay the resulting energy bills. They also have an easier time evacuating their homes before disasters, and recovering afterward. Lower income people have fewer of these advantages, and they are also more likely to live in hotter neighborhoods and work outdoors, where they face the brunt of climate change.

These inequalities will play out on an individual, community, and regional level. A 2017 analysis of the U.S. found that, under business as usual, the poorest one-third of counties, which are concentrated in the South, will experience damages totaling as much as 20 percent of gross domestic product, while others, mostly in the northern part of the country, will see modest economic gains. Solomon Hsiang, an economist at University of California, Berkeley, and the lead author of the study, has said that climate change “may result in the largest transfer of wealth from the poor to the rich in the country’s history.”

Even the climate “winners” will not be immune from all climate impacts, though. Desirable locations will face an influx of migrants. And as the coronavirus pandemic has demonstrated, disasters in one place quickly ripple across our globalized economy. For instance, scientists expect climate change to increase the odds of multiple crop failures occurring at the same time in different places, throwing the world into a food crisis .

On top of that, warmer weather is aiding the spread of infectious diseases and the vectors that transmit them, like ticks and mosquitoes . Research has also identified troubling correlations between rising temperatures and increased interpersonal violence , and climate change is widely recognized as a “threat multiplier” that increases the odds of larger conflicts within and between countries. In other words, climate change will bring many changes that no amount of money can stop. What could help is taking action to limit warming.

One of the most common arguments against taking aggressive action to combat climate change is that doing so will kill jobs and cripple the economy. But this implies that there’s an alternative in which we pay nothing for climate change. And unfortunately, there isn’t. In reality, not tackling climate change will cost a lot , and cause enormous human suffering and ecological damage, while transitioning to a greener economy would benefit many people and ecosystems around the world.

Let’s start with how much it will cost to address climate change. To keep warming well below 2 degrees Celsius, the goal of the Paris Climate Agreement, society will have to reach net zero greenhouse gas emissions by the middle of this century. That will require significant investments in things like renewable energy, electric cars and charging infrastructure, not to mention efforts to adapt to hotter temperatures, rising sea-levels and other unavoidable effects of current climate changes. And we’ll have to make changes fast.

Estimates of the cost vary widely. One recent study found that keeping warming to 2 degrees Celsius would require a total investment of between $4 trillion and $60 trillion, with a median estimate of $16 trillion, while keeping warming to 1.5 degrees Celsius could cost between $10 trillion and $100 trillion, with a median estimate of $30 trillion. (For reference, the entire world economy was about $88 trillion in 2019.) Other studies have found that reaching net zero will require annual investments ranging from less than 1.5 percent of global gross domestic product to as much as 4 percent . That’s a lot, but within the range of historical energy investments in countries like the U.S.

Now, let’s consider the costs of unchecked climate change, which will fall hardest on the most vulnerable. These include damage to property and infrastructure from sea-level rise and extreme weather, death and sickness linked to natural disasters, pollution and infectious disease, reduced agricultural yields and lost labor productivity because of rising temperatures, decreased water availability and increased energy costs, and species extinction and habitat destruction. Dr. Hsiang, the U.C. Berkeley economist, describes it as “death by a thousand cuts.”

As a result, climate damages are hard to quantify. Moody’s Analytics estimates that even 2 degrees Celsius of warming will cost the world $69 trillion by 2100, and economists expect the toll to keep rising with the temperature. In a recent survey , economists estimated the cost would equal 5 percent of global G.D.P. at 3 degrees Celsius of warming (our trajectory under current policies) and 10 percent for 5 degrees Celsius. Other research indicates that, if current warming trends continue, global G.D.P. per capita will decrease between 7 percent and 23 percent by the end of the century — an economic blow equivalent to multiple coronavirus pandemics every year. And some fear these are vast underestimates .

Already, studies suggest that climate change has slashed incomes in the poorest countries by as much as 30 percent and reduced global agricultural productivity by 21 percent since 1961. Extreme weather events have also racked up a large bill. In 2020, in the United States alone, climate-related disasters like hurricanes, droughts, and wildfires caused nearly $100 billion in damages to businesses, property and infrastructure, compared to an average of $18 billion per year in the 1980s.

Given the steep price of inaction, many economists say that addressing climate change is a better deal . It’s like that old saying: an ounce of prevention is worth a pound of cure. In this case, limiting warming will greatly reduce future damage and inequality caused by climate change. It will also produce so-called co-benefits, like saving one million lives every year by reducing air pollution, and millions more from eating healthier, climate-friendly diets. Some studies even find that meeting the Paris Agreement goals could create jobs and increase global G.D.P . And, of course, reining in climate change will spare many species and ecosystems upon which humans depend — and which many people believe to have their own innate value.

The challenge is that we need to reduce emissions now to avoid damages later, which requires big investments over the next few decades. And the longer we delay, the more we will pay to meet the Paris goals. One recent analysis found that reaching net-zero by 2050 would cost the U.S. almost twice as much if we waited until 2030 instead of acting now. But even if we miss the Paris target, the economics still make a strong case for climate action, because every additional degree of warming will cost us more — in dollars, and in lives.

Veronica Penney contributed reporting.

Illustration photographs by Esther Horvath, Max Whittaker, David Maurice Smith and Talia Herman for The New York Times; Esther Horvath/Alfred-Wegener-Institut

An earlier version of this article misidentified the authors of The Debunking Handbook. It was written by social scientists who study climate communication, not a team of climate scientists.

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ENCYCLOPEDIC ENTRY

Global warming.

The causes, effects, and complexities of global warming are important to understand so that we can fight for the health of our planet.

Earth Science, Climatology

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Global warming is the long-term warming of the planet’s overall temperature. Though this warming trend has been going on for a long time, its pace has significantly increased in the last hundred years due to the burning of fossil fuels . As the human population has increased, so has the volume of fossil fuels burned. Fossil fuels include coal, oil, and natural gas, and burning them causes what is known as the “greenhouse effect” in Earth’s atmosphere.

The greenhouse effect is when the sun’s rays penetrate the atmosphere, but when that heat is reflected off the surface cannot escape back into space. Gases produced by the burning of fossil fuels prevent the heat from leaving the atmosphere. These greenhouse gasses are carbon dioxide , chlorofluorocarbons, water vapor , methane , and nitrous oxide . The excess heat in the atmosphere has caused the average global temperature to rise overtime, otherwise known as global warming.

Global warming has presented another issue called climate change. Sometimes these phrases are used interchangeably, however, they are different. Climate change refers to changes in weather patterns and growing seasons around the world. It also refers to sea level rise caused by the expansion of warmer seas and melting ice sheets and glaciers . Global warming causes climate change, which poses a serious threat to life on Earth in the forms of widespread flooding and extreme weather. Scientists continue to study global warming and its impact on Earth.

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What is climate change mitigation and why is it urgent?

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• Climate change mitigation involves actions to reduce or prevent greenhouse gas emissions from human activities.
• Mitigation efforts include transitioning to renewable energy sources, enhancing energy efficiency, adopting regenerative agricultural practices and protecting and restoring forests and critical ecosystems.
• Effective mitigation requires a whole-of-society approach and structural transformations to reduce emissions and limit global warming to 1.5°C above pre-industrial levels.
• International cooperation, for example through the Paris Agreement, is crucial in guiding and achieving global and national mitigation goals.
• Mitigation efforts face challenges such as the world's deep-rooted dependency on fossil fuels, the increased demand for new mineral resources and the difficulties in revamping our food systems.
• These challenges also offer opportunities to improve resilience and contribute to sustainable development.

What is climate change mitigation?

Climate change mitigation refers to any action taken by governments, businesses or people to reduce or prevent greenhouse gases, or to enhance carbon sinks that remove them from the atmosphere. These gases trap heat from the sun in our planet’s atmosphere, keeping it warm. 

Since the industrial era began, human activities have led to the release of dangerous levels of greenhouse gases, causing global warming and climate change. However, despite unequivocal research about the impact of our activities on the planet’s climate and growing awareness of the severe danger climate change poses to our societies, greenhouse gas emissions keep rising. If we can slow down the rise in greenhouse gases, we can slow down the pace of climate change and avoid its worst consequences.

Reducing greenhouse gases can be achieved by:

• Shifting away from fossil fuels : Fossil fuels are the biggest source of greenhouse gases, so transitioning to modern renewable energy sources like solar, wind and geothermal power, and advancing sustainable modes of transportation, is crucial.
• Improving energy efficiency : Using less energy overall – in buildings, industries, public and private spaces, energy generation and transmission, and transportation – helps reduce emissions. This can be achieved by using thermal comfort standards, better insulation and energy efficient appliances, and by improving building design, energy transmission systems and vehicles.
• Changing agricultural practices : Certain farming methods release high amounts of methane and nitrous oxide, which are potent greenhouse gases. Regenerative agricultural practices – including enhancing soil health, reducing livestock-related emissions, direct seeding techniques and using cover crops – support mitigation, improve resilience and decrease the cost burden on farmers.
• The sustainable management and conservation of forests : Forests act as carbon sinks , absorbing carbon dioxide and reducing the overall concentration of greenhouse gases in the atmosphere. Measures to reduce deforestation and forest degradation are key for climate mitigation and generate multiple additional benefits such as biodiversity conservation and improved water cycles.
• Restoring and conserving critical ecosystems : In addition to forests, ecosystems such as wetlands, peatlands, and grasslands, as well as coastal biomes such as mangrove forests, also contribute significantly to carbon sequestration, while supporting biodiversity and enhancing climate resilience.
• Creating a supportive environment : Investments, policies and regulations that encourage emission reductions, such as incentives, carbon pricing and limits on emissions from key sectors are crucial to driving climate change mitigation.

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What is the 1.5°C goal and why do we need to stick to it?

In 2015, 196 Parties to the UN Climate Convention in Paris adopted the Paris Agreement , a landmark international treaty, aimed at curbing global warming and addressing the effects of climate change. Its core ambition is to cap the rise in global average temperatures to well below 2°C above levels observed prior to the industrial era, while pursuing efforts to limit the increase to 1.5°C.

The 1.5°C goal is extremely important, especially for vulnerable communities already experiencing severe climate change impacts. Limiting warming below 1.5°C will translate into less extreme weather events and sea level rise, less stress on food production and water access, less biodiversity and ecosystem loss, and a lower chance of irreversible climate consequences.

To limit global warming to the critical threshold of 1.5°C, it is imperative for the world to undertake significant mitigation action. This requires a reduction in greenhouse gas emissions by 45 percent before 2030 and achieving net-zero emissions by mid-century.

What are the policy instruments that countries can use to drive mitigation?

Everyone has a role to play in climate change mitigation, from individuals adopting sustainable habits and advocating for change to governments implementing regulations, providing incentives and facilitating investments. The private sector, particularly those businesses and companies responsible for causing high emissions, should take a leading role in innovating, funding and driving climate change mitigation solutions. 

International collaboration and technology transfer is also crucial given the global nature and size of the challenge. As the main platform for international cooperation on climate action, the Paris Agreement has set forth a series of responsibilities and policy tools for its signatories. One of the primary instruments for achieving the goals of the treaty is Nationally Determined Contributions (NDCs) . These are the national climate pledges that each Party is required to develop and update every five years. NDCs articulate how each country will contribute to reducing greenhouse gas emissions and enhance climate resilience.   While NDCs include short- to medium-term targets, long-term low emission development strategies (LT-LEDS) are policy tools under the Paris Agreement through which countries must show how they plan to achieve carbon neutrality by mid-century. These strategies define a long-term vision that gives coherence and direction to shorter-term national climate targets.

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Photo: William Seal/UNDP Sudan

At the same time, the call for climate change mitigation has evolved into a call for reparative action, where high-income countries are urged to rectify past and ongoing contributions to the climate crisis. This approach reflects the UN Framework Convention on Climate Change (UNFCCC) which advocates for climate justice, recognizing the unequal historical responsibility for the climate crisis, emphasizing that wealthier countries, having profited from high-emission activities, bear a greater obligation to lead in mitigating these impacts. This includes not only reducing their own emissions, but also supporting vulnerable countries in their transition to low-emission development pathways.

Another critical aspect is ensuring a just transition for workers and communities that depend on the fossil fuel industry and its many connected industries. This process must prioritize social equity and create alternative employment opportunities as part of the shift towards renewable energy and more sustainable practices.

For emerging economies, innovation and advancements in technology have now demonstrated that robust economic growth can be achieved with clean, sustainable energy sources. By integrating renewable energy technologies such as solar, wind and geothermal power into their growth strategies, these economies can reduce their emissions, enhance energy security and create new economic opportunities and jobs. This shift not only contributes to global mitigation efforts but also sets a precedent for sustainable development.

What are some of the challenges slowing down climate change mitigation efforts?

Mitigating climate change is fraught with complexities, including the global economy's deep-rooted dependency on fossil fuels and the accompanying challenge of eliminating fossil fuel subsidies. This reliance – and the vested interests that have a stake in maintaining it – presents a significant barrier to transitioning to sustainable energy sources.

The shift towards decarbonization and renewable energy is driving increased demand for critical minerals such as copper, lithium, nickel, cobalt, and rare earth metals. Since new mining projects can take up to 15 years to yield output, mineral supply chains could become a bottleneck for decarbonization efforts. In addition, these minerals are predominantly found in a few, mostly low-income countries, which could heighten supply chain vulnerabilities and geopolitical tensions.

Furthermore, due to the significant demand for these minerals and the urgency of the energy transition, the scaled-up investment in the sector has the potential to exacerbate environmental degradation, economic and governance risks, and social inequalities, affecting the rights of Indigenous Peoples, local communities, and workers. Addressing these concerns necessitates implementing social and environmental safeguards, embracing circular economy principles, and establishing and enforcing responsible policies and regulations .

Agriculture is currently the largest driver of deforestation worldwide. A transformation in our food systems to reverse the impact that agriculture has on forests and biodiversity is undoubtedly a complex challenge. But it is also an important opportunity. The latest IPCC report highlights that adaptation and mitigation options related to land, water and food offer the greatest potential in responding to the climate crisis. Shifting to regenerative agricultural practices will not only ensure a healthy, fair and stable food supply for the world’s population, but also help to significantly reduce greenhouse gas emissions.  

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Photo: Nino Zedginidze/UNDP Georgia

What are some examples of climate change mitigation?

In Mauritius , UNDP, with funding from the Green Climate Fund, has supported the government to install battery energy storage capacity that has enabled 50 MW of intermittent renewable energy to be connected to the grid, helping to avoid 81,000 tonnes of carbon dioxide annually. 

In Indonesia , UNDP has been working with the government for over a decade to support sustainable palm oil production. In 2019, the country adopted a National Action Plan on Sustainable Palm Oil, which was collaboratively developed by government, industry and civil society representatives. The plan increased the adoption of practices to minimize the adverse social and environmental effects of palm oil production and to protect forests. Since 2015, 37 million tonnes of direct greenhouse gas emissions have been avoided and 824,000 hectares of land with high conservation value have been protected.

In Moldova and Paraguay , UNDP has helped set up Green City Labs that are helping build more sustainable cities. This is achieved by implementing urban land use and mobility planning, prioritizing energy efficiency in residential buildings, introducing low-carbon public transport, implementing resource-efficient waste management, and switching to renewable energy sources. 

UNDP has supported the governments of Brazil, Costa Rica, Ecuador and Indonesia to implement results-based payments through the REDD+ (Reducing emissions from deforestation and forest degradation in developing countries) framework. These include payments for environmental services and community forest management programmes that channel international climate finance resources to local actors on the ground, specifically forest communities and Indigenous Peoples. 

UNDP is also supporting small island developing states like the Comoros to invest in renewable energy and sustainable infrastructure. Through the Africa Minigrids Program , solar minigrids will be installed in two priority communities, Grand Comore and Moheli, providing energy access through distributed renewable energy solutions to those hardest to reach.

And in South Africa , a UNDP initative to boost energy efficiency awareness among the general population and improve labelling standards has taken over commercial shopping malls.

What is UNDP’s role in supporting climate change mitigation?

UNDP aims to assist countries with their climate change mitigation efforts, guiding them towards sustainable, low-carbon and climate-resilient development. This support is in line with achieving the Sustainable Development Goals (SDGs), particularly those related to affordable and clean energy (SDG7), sustainable cities and communities (SDG11), and climate action (SDG13). Specifically, UNDP’s offer of support includes developing and improving legislation and policy, standards and regulations, capacity building, knowledge dissemination, and financial mobilization for countries to pilot and scale-up mitigation solutions such as renewable energy projects, energy efficiency initiatives and sustainable land-use practices. 

With financial support from the Global Environment Facility and the Green Climate Fund, UNDP has an active portfolio of 94 climate change mitigation projects in 69 countries. These initiatives are not only aimed at reducing greenhouse gas emissions, but also at contributing to sustainable and resilient development pathways.

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Ho Tuan Anh delivers goods with his new e-motorbike. Photo by: Phan Huong Giang/UNDP Viet Nam

Why the Western Balkans are choosing decarbonization

Photo: UNDP Bosnia and Herzegovina

Six lessons on how to achieve future-smart energy efficient buildings 

Solar photovoltaic systems on roofs in Lebanon. Photo: Fouad Choufany / UNDP Lebanon

Six ways to achieve sustainable energy for all

Photo: UNDP Zimbabwe

Are humans causing or contributing to global warming?

Yes, by increasing the abundance of greenhouse gases in the atmosphere, human activities are amplifying Earth’s natural greenhouse effect. Virtually all climate scientists agree that this increase in heat-trapping gases is the main reason for the 1.8°F (1.0°C) rise in global average temperature since the late nineteenth century. Carbon dioxide, methane, nitrous oxide, ozone, and various chlorofluorocarbons are all human-emitted  heat-trapping gases . Among these, carbon dioxide is of greatest concern to scientists because it exerts a larger overall warming influence than the  other gases combined .

Steam billows from the Intermountain Power Plant in Delta, Utah. This coal-fired plant is operated by the Los Angeles Department of Water and Power. Photo CC license by Matt Hintsa .

At present, humans are putting an estimated 9.5 billion metric tons of carbon into the atmosphere each year by burning fossil fuels, and another 1.5 billion through deforestation and other land cover changes. Of this human-produced carbon, forests and other vegetation absorb around 3.2 billion metric tons per year, while the ocean absorbs about 2.5 billion metric tons per year. A net 5 billion metric tons of human-produced carbon remain in the atmosphere each year, raising the global average carbon dioxide concentrations by about 2.3 parts per million per year. Since 1750, humans have increased the abundance of carbon dioxide in the atmosphere by nearly 50 percent.  Learn more .

USGCRP (2017). Climate Science Special Report: Fourth National Climate Assessment, Volume 1 [Wuebbles, D.J., D.W. Fahey, K.A. Hibbard, D.J. Dokken, B.C. Stewart, and T.K. Maycock (eds.)]. U.S. Global Change Research Program, Washington, DC, USA, 470 pp, doi:  10.7930/J0J964J6 .

Friedlingstein, P., Jones, M. W., O’Sullivan, M., Andrew, R. M., Hauck, J., Peters, G. P., Peters, W., Pongratz, J., Sitch, S., Le Quéré, C., Bakker, D. C. E., Canadell, J. G., Ciais, P., Jackson, R. B., Anthoni, P., Barbero, L., Bastos, A., Bastrikov, V., Becker, M., … Zaehle, S. (2019). Global carbon budget 2019. Earth System Science Data, 11(4), 1783–1838. https://doi.org/10.3929/ethz-b-000385668

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Aerial view of a wind farm at Pen y Cymoedd in south Wales, UK. Wind-generated power in the UK increased by 83% between 2015 and 2020 to provide nearly a quarter of our electricity . It's also one of the fastest-growing renewable energy technologies globally. © Richard Whitcombe/ Shutterstock

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Renewable energy and its importance for tackling climate change

Replacing fossil fuel-reliant power stations with renewable energy sources, such as wind and solar, is a vital part of stabilising climate change and achieving net zero carbon emissions.

Professor Magda Titirici , Chair in Sustainable Energy Materials at Imperial College London, offers an introduction to renewable energy and the future of clean, green power in the UK.

What is renewable energy?

Renewable energy comes from sources that replenish naturally and continually within a human lifetime. Renewable energy is often called sustainable energy.

Major sources of renewable energy include solar, wind, hydroelectric, tidal, geothermal and biomass energy, which is derived from burning plant or animal matter and waste.

Switching our reliance on fossil fuels to renewable energy sources that produce lower or no greenhouse gas emissions is critically important in tackling the climate crisis .

Clean, green or renewable - what's the difference?

Clean energy doesn't produce any pollution once installed. Nor does green energy, which comes from natural sources such as the Sun and is produced without any major negative impacts on the environment. Renewable energy refers to sources that are constantly replenished.

While there is often overlap between these definitions and most renewable energy sources can also be considered clean and green, it's not always the case.

Nuclear energy doesn't release greenhouse gases into the atmosphere, so some people consider it to be clean - providing the radioactive waste is stored safely and doesn't escape into the environment. But the uranium energy source used in nuclear power plants isn't renewable.

A coal power plant emitting smoke, steam and carbon dioxide. Fossil fuels such as coal are non-renewable resources. Burning fossil fuels contributes to climate change by releasing greenhouse gases into the atmosphere. © Peter Gudella/ Shutterstock

What's the difference between renewable and non-renewable energy?

Non-renewable energy comes from natural resources such as coal, oil and natural gas that take billions of years to form, which is why we call them fossil fuels. They are present in finite amounts and will run out, as we are using them far more quickly than they form.

When will fossil fuels run out?

Research based on 2015 data predicts that coal stocks will last well into the next century, but oil and natural gas reserves (stocks that we know we can extract from) will run out in the late 2060s . However, scientific models suggest that if we are to limit global warming to 2°C - the target agreed at COP26 is 1.5°C - over 80% of coal, 50% of gas and 30% of oil reserves will need to be left untouched anyway.

When we extract fossil fuels from deep within the planet and burn them, we can generate electricity quite efficiently. But the process releases a lot of carbon dioxide (CO 2 ) into the atmosphere, which contributes to the greenhouse effect, global warming and biodiversity loss .

Magda explains, 'Fossil fuels brought with them immense technological progress but using them releases CO 2 into the atmosphere, which acts like a blanket, trapping heat that would otherwise escape into space and causing global warming.'

Did you know?

The energy sector is responsible for almost three-quarters of the emissions that have caused global temperatures to warm by 1.1°C since pre-industrial times. 

If we continue to use fossil fuels, the effect will only worsen.

Magda adds, 'If we want to live on this planet much longer than 2050 and keep temperature levels below the 1.5°C of warming agreed to by governments around the world, we need to make some radical changes right now. We need to move to technologies that will give us the same level and comfort of living but drastically cut our emissions and carbon footprint .'

Examples of renewable energy sources

The main types of renewable energy are wind, solar, hydroelectric, tidal, geothermal and biomass. Read on to discover the pros and cons of each of these renewable energy sources.

One of the main benefits of most renewable energy sources is that they don't release carbon dioxide or pollute the air when they are used to produce electricity or heat. Greenhouse gases are emitted during the lifetime of some of the technologies - for example, during their manufacture or construction - but overall emissions are significantly lower than for fossil fuels.

Whereas some countries lack direct access to fossil fuels and must rely on international sources, renewable energy often allows countries to supply their own energy needs, a big economic and political advantage.

Wind energy

An offshore wind farm in the North Sea off the UK coast. Wind energy is an important renewable resource for the UK. According to analysis by Imperial College London's Energy Institute , offshore wind turbines offer the best-value option for meeting the UK's target of delivering carbon neutral electricity by 2035. But the UK's current target for offshore wind electricity production - up to 50 gigawatts by 2030 - will need to be significantly increased to do so. © Riekelt Hakvoort/ Shutterstock

Wind power converts wind - the movement of air - into stored power by turning turbines and converting mechanical energy into electricity. Wind farms can be built both on land and offshore. They work well wherever wind is strong and reliable.

Advantages: Wind energy is a clean, green and renewable resource and turbines can be placed on farmland with minimal disruption. It has the lowest carbon footprint of all renewable energy sources .

Disadvantages: Like any infrastructure, there is an upfront establishment cost and ongoing maintenance fees. These are even higher if wind farms are built offshore. Turbines have a reputation for being noisy and poorly sited wind farms can be dangerous to some wildlife - for instance, if they're placed in the migration paths of birds or bats.

How loud is a wind turbine?

At 300 metres from a dwelling, wind turbines have a sound pressure of 43 decibels , which is between the volume of a refrigerator and an air conditioner.

Solar energy

An array of solar panels in a field in Chippenham, UK. Solar energy is a renewable resource, and the Sun provides more energy than we'll ever use. If we could capture it all, an hour of sunlight would meet the world's energy needs for a year. © Alexey Fedorenko/ Shutterstock

Solar power captures energy (radiation) from the Sun and converts it into electricity, which is then fed into a power grid or stored for later use. Although places near the equator receive the most solar energy, solar panels can generate electricity anywhere that gets sunlight.

Advantages:  Solar energy is renewable, clean, increasingly efficient and has low maintenance costs. Once established, it can dramatically reduce the price of generating electricity.

Disadvantages:  Setting up a solar array is costly and there are expenses involved with energy storage. Solar panels can take up more land than some other types of renewable energy and performance depends on the availability of sunlight. The mining and processing of minerals needed to make the panels can pollute and damage the environment.

China is currently leading the world in solar energy production , with roughly 35% of the global market.

Hydroelectric energy

Although hydroelectric energy is renewable, it is not always considered green, as building large-scale dams can negatively impact the environment. Nepean Dam in Australia, shown here, was included in a study that showed dams are causing problems for platypuses by creating a barrier between populations. © Greg Brave/ Shutterstock

Hydroelectric power uses the flow of water, often from rivers and lakes controlled by a dam, to turn turbines and power generators, creating electricity. Hydropower works best for regions with reliable rainfall and large, natural water reservoirs.

Hydropower currently produces more electricity than  all other renewable energy sources combined and provides around 17% of the world's energy.

Advantages: Hydroelectricity is dependable and renewable for as long as there is rainfall or flowing water. Reservoirs can offer additional benefits, such as providing drinking water, irrigation and recreational opportunities, including swimming or boating.

Disadvantages: Hydropower plants take up a lot of room and aren't suited to all climates. They are susceptible to drought. Creating artificial water reservoirs can harm biodiversity in natural water systems by limiting the inflow of nutrients and blocking the journey of migratory fish populations. These reservoirs can also release methane - a type of greenhouse gas - as vegetation in the flooded area decomposes. Large amounts of cement are used to construct dams. The manufacture of this material produces large amounts of carbon dioxide.

Tidal energy

Renewable tidal energy is produced by the natural rise and fall of the sea. However, tidal power plants can change the local biodiversity. This one on the River Rance in Brittany, France, not only led to the local extinction of a fish called plaice but to an increase in the number of cuttlefish, which now thrive there. © Francois BOIZOT/ Shutterstock

Tidal energy uses the continual movement of ocean tides to generate power. Turbines in the water turn a generator, creating electricity.

Advantages: Tidal energy is renewable, generates no carbon emissions and can produce a lot of energy very reliably.

Disadvantages: Offshore infrastructure is expensive to set up and maintain and there are a limited number of appropriate sites for tidal power plants around the world. They can also damage marine environments and impact local plants and animals.

Geothermal energy

A geothermal power plant in Iceland harnesses this renewable energy source. © Peter Gudella/ Shutterstock

Geothermal power uses underground reservoirs of hot water or steam created by the heat of Earth's core to generate electricity. It works best in regions near tectonic plate boundaries .

Advantages: Geothermal energy is highly reliable and has a consistent power output. It also has a relatively small footprint on the land.

Disadvantages: Drilling geothermal wells is expensive and can affect the stability of surrounding land. It must be monitored carefully to minimise environmental impact. There is also a risk of releasing greenhouse gases trapped under Earth's surface.  

Biomass energy

A biogas plant producing renewable energy from biomass in the Czech Republic. © Kletr/ Shutterstock

Biomass energy comes from burning plants, plant by-products or waste. Examples include ethanol (from corn or sugarcane), biodiesel (made from vegetable oils, used cooking oils and animal fats), green diesel (derived from algae, sustainable wood crops or sawdust) and biogas (derived from animal manure and other waste).

Advantages: Abundant and cheaply produced, biomass energy is a novel use of waste product and leftover crops. It creates less emissions than burning fossil fuels and having carbon capture in place can stop carbon dioxide entering the atmosphere. Biofuels are also considered relatively easy and inexpensive to implement, as they are compatible with existing agriculture and waste processing and used in existing petrol and diesel vehicles.

Disadvantages: Generating biofuels requires land and water so growing demand for them could lead to deforestation and biodiversity loss. Burning biomass emits carbon dioxide unless carbon capture is implemented.

Ethanol-powered vehicles create up to 86% less greenhouse gas emissions than petrol vehicles, and crops that are grown to produce biomass absorb carbon dioxide.

Can renewable energy replace fossil fuels in the UK?

In 2020, 42% of the UK's electricity came from renewable energy. A quarter of the UK's electricity was produced by wind power, which is the highest proportion of any G20 country and more than four times the global average. Statistics on UK energy trends reveal that from April to June 2022, nearly 39% of the UK's electricity came from renewable energy, slightly more than during the same period in 2021, but down from 45.5% between January and March 2022 when it was unusually sunny and wind speeds were high.

'There has been good news in recent years in terms of progress on renewables,' says Magda, 'but in my opinion, the UK is still lagging behind. It is not so strong yet for truly sustainable technologies. It needs storage and conversion.'

Magda believes that wind (particularly offshore), solar, green hydrogen and rapid innovation in battery storage will be key to the UK reaching net zero by 2050.

She explains, 'The UK is a really windy place, so wind is the perfect renewable energy technology. By 2035 wind and solar should provide 75-90% of total UK electricity to bring emissions down significantly.'

'It has already been shown that it's feasible to produce 90% of the UK's electricity from wind and solar combined. The tech is there and it's becoming more efficient and affordable each year.'

'Offshore wind capacity will also help produce green hydrogen, another crucial part of the UK decarbonisation path.'

What is green hydrogen?

Green hydrogen is a fuel created using renewable energy in a process known as electrolysis. When green hydrogen is burned to produce energy, it releases water.

It's predicted that the UK will need 100 terawatt-hours of green hydrogen by 2035.

What is a terawatt-hour?

A terawatt-hour is a unit of measurement that's large enough to describe the annual electricity needs of entire countries. For scale, one terawatt-hour is equivalent to burning 588,441 barrels of oil.

The future of renewable energy in the UK

Magda believes the UK is at a very critical point in its sustainable technologies journey.

'Everything will depend on what happens this year and next. We need to see radical changes, investment, subsidies and support to reach our target of net zero by 2050.'

'It would cost less than 1% of GDP to get to net zero by 2050 but the advantages would be immense: new jobs, a sustainable economy and a healthy and resilient society.'

An empty electric vehicle charging point © Tony Skerl/ Shutterstock

Challenges and opportunities for renewable energy in the UK

One of the biggest challenges the UK is facing right now is battery storage and access to materials like cobalt and lithium , which are needed to produce lithium-ion batteries at scale.

Why are batteries important for renewable energy?

Batteries help make renewable energy supply reliable and portable - such as in the case of electric vehicles.

Batteries are an important part of our transition to renewable technologies, as they allow energy to be stored and released as needed. For example, solar panels generate energy during the day, and batteries make it possible to store and use that electricity at night.

Currently, just a few countries are responsible for most of the world's production of lithium.

According to Magda, the UK lacks access to the supply chain needed for Li-ion batteries. 'As a result, she adds, 'Johnson Matthey, which is a major company driving battery innovations in the UK, announced they would stop lithium battery research because they are unable to secure a path to raw materials and be competitive on the international market.'

Museum researchers are investigating whether it would be possible to develop a  more sustainable, domestic supply chain by extracting lithium from UK rocks. They made a key breakthrough in 2021 when they produced battery-grade lithium chemicals from UK rocks for the first time.

According to Professor Richard Herrington, Head of Earth Sciences at the Museum, 'An increased, reliable supply of lithium is critical if we are to meet the rising demand for electric cars and provide a dependable supply of energy from renewable sources. The next generation of batteries that don't require lithium may still be three to five years away from being ready for public use.'

However, Magda is optimistic that the UK could lead in emerging battery technologies. 'I think the UK has an amazing opportunity to pioneer the next generation of batteries,' she says.

Innovative models already under development at The Faraday Institution include:

• Sodium-ion batteries, which are based on waste-derived anodes and critical metal -free cathodes, provide almost the same performance as lithium-ion batteries at half the cost.
• Lithium-sulphur batteries with 10 times the energy density of lithium-ion batteries make more efficient use of limited materials and eliminate metals from the cathode by using sulphur instead.

Magda adds, 'We need to focus on the areas where the UK has the potential to lead. The UK has such a big tradition in new materials and discoveries, we could move to completely new technologies both for batteries and hydrogen production.'

'There are a lot of challenges, but if we're investing in it, we could be future leaders and even solve one of the most difficult challenges in decarbonisation: flight.'

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