Climate change denial, also called global warming denial, is a type of science denial. It involves refusing to accept, ignoring, or arguing against the strong scientific evidence that shows human activities cause global warming. People who promote denial often use speaking strategies to create the false idea that scientists disagree about climate change when they actually agree. Climate change denial includes questioning how much humans contribute to climate change, downplaying its effects on nature and people, and making the costs of reducing climate change seem high while making the costs of dealing with its effects seem low. Sometimes, people may not directly deny the science but still struggle to act on it because of their beliefs or actions. Studies have shown that these views are linked to denialism, false science, or misleading information.

Many topics that scientists agree on, like human responsibility for climate change, are still challenged by groups trying to reduce their importance for political or economic reasons. This is called climate change denial. Scientists, especially in the United States, have reported being pressured by governments or oil companies to hide their research or avoid talking about climate change publicly. The fossil fuel industry has supported efforts to weaken or question the scientific agreement on climate change.

Groups with industrial, political, or ideological goals work to reduce public trust in climate science. Climate change denial is connected to the fossil fuel industry, the Koch brothers, industry supporters, very conservative think tanks, and conservative media, often in the United States. More than 90% of research that questions climate change comes from right-wing think tanks. Climate change denial makes it harder to take action against or prepare for climate change and strongly influences climate-related politics.

In the 1970s, oil companies shared research that matched the scientific community’s view on climate change. However, for many years after, oil companies organized large, planned efforts to spread false information about climate change. These actions are similar to how the tobacco industry once denied the dangers of smoking. Some of these campaigns are led by people who previously spread false information about tobacco.

Terminology

Climate change denial means not believing, ignoring, or questioning the scientific agreement about how fast and how much the climate is changing, how important these changes are, or how they are connected to human actions. This type of denial is a form of rejecting science. It can sometimes include false scientific claims. The terms "climate skeptics" or "contrarians" are now used to describe people who deny climate change, even though many of them prefer not to be called this. They use these terms to create confusion about their real goals.

There is debate about the best words to use. Most people who reject the scientific agreement prefer to be called "skeptics" or to use the term "climate change skepticism." However, the word "skepticism" is not correct in this context because scientific skepticism is a normal part of how science works. All scientists use skepticism as part of the process of asking questions and testing ideas. Both "skepticism" and "denial" are not ideal, but "climate change denial" is now more commonly used than "skepticism."

The term "contrarian" is more specific but is used less often. In academic writing and journalism, the terms "climate change denial" and "climate change deniers" are widely accepted as neutral, descriptive terms without negative meanings.

The use of these terms began in the 1990s. By 1995, the word "skeptic" was used to describe a small group of people who publicly shared views that disagreed with the scientific agreement. These individuals shared their ideas in the media rather than with other scientists. In 1995, journalist Ross Gelbspan wrote that industries had paid a small group of "skeptics" to confuse the public about climate change. His 1997 book, The Heat is On, focused on this issue, describing a campaign to deny global warming and hide the truth about climate change.

In December 2014, the Committee for Skeptical Inquiry asked the media to stop using the word "skeptic" when talking about people who deny climate change. They explained that scientific skepticism is part of the scientific process, but denial means rejecting ideas without looking at the facts. They said that not all people who call themselves "climate change skeptics" are deniers, but most deniers falsely claim to be skeptics. This misuse of the word has given false credibility to people who reject science.

In 2015, The New York Times said it would use the word "denier" when someone challenges well-known scientific facts, but only after checking each case individually. The Society of Environmental Journalists said "denier" is the best term for people who claim global warming does not exist or who say it has no causes or effects that can be measured.

A group called climatetruth.org asked the Associated Press to stop using "skeptic" to describe people who deny scientific facts. In September 2015, the Associated Press updated its stylebook, suggesting that people who do not accept climate science should be called "climate change doubters" or "those who reject mainstream climate science." They advised avoiding "skeptics" or "deniers." In May 2019, The Guardian also stopped using "climate skeptic" and instead used "climate science denier."

In addition to openly denying climate change, some people show a form of hidden denial by accepting the scientific agreement but not taking action. This is called "soft climate change denial."

Categories and tactics

In 2004, German climate scientist Stefan Rahmstorf explained how the media sometimes create a false idea that scientists disagree about climate change. He said this happens because people who doubt climate change use strategies to spread their views. He also grouped different types of climate change skepticism into categories. Later, this system was used to describe denial of climate change as well:

• Trend skeptics or deniers (who say there is no major warming): "Now, most people can see that the Earth is warming. Trend skeptics say the warming measured by weather stations is not real but caused by cities growing around those stations (urban heat island effect)."
• Attribution skeptics or deniers (who agree warming is happening but say it is caused by natural factors, not humans): "Some of them say the increase in carbon dioxide in the air is not from human activity. Instead, they claim the air’s carbon dioxide comes from the ocean naturally."
• Impact skeptics or deniers (who say climate change is not harmful or even helpful, like more farming areas in cold regions).
• Consensus denial (when people question whether scientists agree that humans cause climate change).

The National Center for Science Education describes climate change denial as arguing against parts of the scientific agreement about climate change. These arguments range from denying that climate change is happening, to accepting it but saying humans are not the cause, to accepting that humans are responsible but denying the effects, or accepting the effects but saying humans cannot solve the problem. James L. Powell and climatologist Michael E. Mann created more detailed lists of these arguments. Mann’s model shows how deniers gradually accept some points but still reject the main scientific agreement.

Climate change denial is a form of denialism. Chris and Mark Hoofnagle define denialism as using persuasive techniques to make it seem like there is a real scientific debate when there is not. This approach aims to reject ideas that most scientists agree on. Common tactics include:

• Saying scientists are hiding the truth or making up data (a climate change conspiracy theory).
• Using people who do not agree with scientific findings to challenge experts, even though these people are not recognized as authorities.
• Choosing only a few old or unusual studies to support their views, like how some groups used a single paper to spread false ideas about vaccines.
• Asking for impossible proof, claiming that any uncertainty in science means the whole field is wrong.
• Using logical mistakes in their arguments.

Some politicians and groups say that carbon dioxide, which is only 0.04% of the air, cannot cause climate change. Scientists have known for over 100 years that even small amounts of carbon dioxide have a strong warming effect. Doubling its amount in the air would cause a large rise in temperature. Some groups say water vapor is a bigger greenhouse gas and is not included in climate models. However, water vapor stays in the air for only about 10 days, while carbon dioxide stays for hundreds of years. This means carbon dioxide is the main cause of warming, and water vapor helps make warming worse after it starts.

Climate denial groups sometimes say global warming has stopped or that the Earth is cooling. These claims are based on short-term changes in temperature but ignore the long-term trend of rising temperatures.

Some groups, like William Happer, argue that adding more greenhouse gases to the air has little effect because the atmosphere becomes "saturated" with them. This is true in some ways, but it is not enough to stop global warming.

Climate denial groups often suggest waiting for better technology to solve climate change. This belief, called techno-optimism, assumes that new inventions will fix the problem without needing changes in society.

Denial groups also say natural events, like sunspots or cosmic rays, cause warming. Scientists already include these factors in their models. The scientific agreement is that these natural events cannot explain the recent warming.

In 2007, the Heartland Institute published a list of 500 scientists who supposedly disagreed with the idea that humans cause global warming. The list was quickly criticized because it misunderstood or misused the scientists’ work. Many scientists on the list did not agree with the article and asked to have their names removed. The Heartland Institute refused, saying scientists had no right to demand their names be taken off.

Denial groups often criticize the IPCC (Intergovernmental Panel on Climate Change) by attacking its reports, scientists, or summaries. The full reports are rarely discussed.

In 1996, Frederick Seitz, a climate change denier, claimed the 1995 IPCC report was biased. Scientists disagreed, saying his claims were part of an effort to harm the scientific process.

In 2005, the House of Lords Economics Committee said it had concerns about the IPCC’s process, claiming some reports were influenced by politics. The UK government disagreed with these claims.

In 2008, a U.S. Senate report led by Jim Inhofe, a major climate change denier, said the IPCC process was unfair. Many details in the report were disputed, including whether the people listed were real scientists or agreed with the report’s claims. Inhofe compared the IPCC process to a "Soviet-style trial" where facts are decided before evidence is considered.

Some climate change deniers spread conspiracy theories, claiming scientists are hiding the truth or working together to mislead the public.

Psychology

The psychology of climate change denial is the study of why some people refuse to believe in climate change, even though scientists widely agree that it is happening. A study examined how people think about and act on climate change based on their beliefs, and found seven psychological barriers that stop people from taking actions that could help reduce harm, prepare for changes, and protect the environment. These barriers include how people think, their political or moral beliefs, how they compare themselves to others, the costs and effort needed to change, not trusting experts, thinking changes are not risky, and not making enough changes in their behavior. Other factors that affect how people respond include how far away the effects of climate change seem in time, place, or influence.

People may feel emotions like worry, sadness, hopelessness, confusion, uncertainty, fear, and stress when thinking about climate change. One psychologist said that feeling hopeless about climate change might make it harder to solve the problem. The American Psychological Association has asked psychologists and other scientists to study how these psychological barriers stop people from taking action on climate change. The increasing number of extreme weather events happening now may encourage people to address climate change more quickly.

A study published in PLOS One in 2024 found that repeating a statement, even once, can make people think it is more true, whether the statement supports climate science or challenges it. This shows how repeating ideas can subtly influence people's beliefs. This effect was seen even among people who already support climate science.

Connections to other debates

Many people who do not believe in climate change have disagreed with the scientific agreement on other environmental issues, such as the thinning of the ozone layer, the use of DDT, and the dangers of second-hand smoke.

In the 1990s, the Marshall Institute worked to oppose stricter rules on environmental problems like acid rain, ozone depletion, second-hand smoke, and the risks of DDT. They argued that the science was not clear enough to support government action, a method they used earlier when trying to reduce attention to the health risks of tobacco in the 1980s. This effort continued for about 20 years.

In 2023, more people began to doubt climate change, especially those who support far-right political groups. Some believe that climate change challenges nationalistic views because it cannot be solved by one country alone and needs teamwork between nations or communities. This has led some nationalist groups to reject scientific evidence about climate change.

The UK Independence Party’s position on climate change has been influenced by Christopher Monckton, a climate change skeptic, and Roger Helmer, who has claimed that the rise in carbon dioxide in the atmosphere may not be caused by humans.

Jerry Taylor of the Niskanen Center says that denying climate change is a key part of the ideas behind Trumpism, a political movement.

Although climate change denial seemed to be decreasing around 2021, some right-wing groups have created new ideas called "environmental populism." These groups argue that natural resources should be kept for current residents of a country and not shared with immigrants. Others claim that people from poor countries cause pollution and climate change and should not be allowed to move to richer countries.

A study in PLOS Climate looked at two types of national identity: "national narcissism," which is the belief that one’s country is special and deserves recognition, and "secure national identification," which is the feeling of strong connection and satisfaction with one’s group. The study found that people with secure national identification are more likely to support policies that reduce climate change and use renewable energy. However, people with national narcissism are less likely to support such policies, unless the policies improve a country’s image. Right-wing political views, which may make people more likely to believe in climate-related conspiracy theories, were also linked to less support for real climate action.

One belief that often leads to climate change denial is support for free enterprise capitalism. This system allows people to use natural resources freely, which can harm ecosystems. People who believe in this system are less likely to support actions that reduce climate change. Political views strongly influence how people think about environmental policies. Liberals usually focus on environmental risks, while conservatives often emphasize the benefits of economic growth. This difference causes disagreements about whether climate change is real.

A study of public opinion from Gallup surveys between 2001 and 2010 found that conservative white men in the U.S. are more likely than others to deny climate change. Those who say they understand climate change well are even more likely to deny it.

Another reason for the difference between liberals and conservatives in believing climate change is that environmental discussions often focus on moral concerns like helping others and avoiding harm, which are more important to liberals. If these discussions instead focus on moral concerns like keeping things clean, which are more important to conservatives, the difference in beliefs may be smaller.

In the U.S., belief in climate change is strongly linked to political party. This is partly because Democrats support stronger government rules and taxes, which are used for environmental policies. Political views also affect how people interpret facts. People with more education are less likely to rely on their own opinions or political beliefs and more likely to trust scientists. This means that political beliefs often influence how people understand climate facts and evidence.

Being part of a political group is a major part of identity for many people, especially in the U.S. Because of this, people often follow the values of their group, even if they disagree with them personally, to avoid being rejected by others in the group.

History

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Since the late 1980s, a well-organized and well-supported effort by scientists with opposing views, free-market think tanks, and industry groups has created a lot of confusion about climate change. Through advertisements, opinion articles, lobbying, and media attention, people who question the effects of greenhouse gases (they prefer not to be called deniers) first claimed that the world is not warming, saying that measurements showing warming are incorrect. Later, they said that any warming is natural, not caused by human activities. Now, they argue that the warming to come will be very small and not harmful.

U.S. fossil fuel companies have known about global warming since at least the 1960s. In 1966, a coal industry research organization, Bituminous Coal Research Inc., published a report stating that if coal consumption continued at its current rate, "the temperature of the earth's atmosphere will increase" and "vast changes in the climates of the earth will result." The report also said that such temperature changes would cause the polar icecaps to melt, which could lead to the flooding of many coastal cities, including New York and London. In a discussion following this paper, a combustion engineer for Peabody Coal, now Peabody Energy, the world's largest coal supplier, said that the coal industry was "buying time" before more government air pollution regulations would be introduced. However, the coal industry publicly supported the idea for many years that increased carbon dioxide in the atmosphere is helpful for the planet.

Contrary to some popular articles from the 1970s, there was no scientific agreement that an ice age was coming. At that time, most scientific research suggested that human activities could cause warming. As public awareness of the greenhouse effect grew in the 1970s, conservative groups began to oppose environmental concerns that might lead to government regulation. In 1977, the first Secretary of Energy, James Schlesinger, suggested President Jimmy Carter take no action on a climate change memo, citing uncertainty. During the presidency of Ronald Reagan, global warming became a political issue, with plans to reduce spending on environmental research, especially climate-related research, and to stop funding for monitoring carbon dioxide levels. Congressman Al Gore was aware of the science: he worked with others to arrange congressional hearings starting in 1981, with scientists like Revelle, Stephen Schneider, and Wallace Smith Broecker testifying.

An Environmental Protection Agency (EPA) report in 1983 said that global warming was "not a theoretical problem but a threat whose effects will be felt within a few years" and could have "catastrophic" consequences. The Reagan administration called the report "alarmist," and the debate was widely covered in the media. Public attention shifted to other issues, and in 1985, the discovery of a hole in the polar ozone layer led to a quick international response. Although this was related to climate change and the possibility of taking action, public interest soon faded.

Public attention returned when summer droughts and heat waves occurred, and James Hansen testified before a Congressional hearing on June 23, 1988, stating with confidence that long-term warming was happening and that severe warming was likely within the next 50 years, with warnings of more frequent storms and floods. There was more media attention: the scientific community had reached a general agreement that the climate was warming, human activity was likely the main cause, and there would be serious consequences if the trend was not stopped. These facts encouraged discussions about new environmental regulations, which the fossil fuel industry opposed.

From 1989 onward, organizations funded by industry groups, such as the Global Climate Coalition and the George C. Marshall Institute, tried to spread doubt using a strategy similar to that used by the tobacco industry. A small group of scientists who disagreed with the scientific consensus on global warming became politically active, and with support from conservative political interests, they started publishing their views in books and the press instead of scientific journals. Historian Spencer Weart says this was the time when skepticism about basic climate science was no longer reasonable, and those spreading doubt became known as deniers. As more scientific evidence refuted their claims, deniers turned to political arguments, attacked scientists' reputations, and promoted ideas of global warming conspiracies.

With the fall of communism in 1989, U.S. conservative think tanks, which had been formed in the 1970s as a counter to socialism, shifted their focus from the "red scare" to the "green scare" tactic, which they saw as a threat to their goals of private property, free market economies, and global capitalism. They used environmental skepticism to deny problems like loss of biodiversity and climate change.

The campaign to spread doubt continued into the 1990s, including an advertising campaign funded by coal industry supporters that aimed to "reposition global warming as theory rather than fact." In 1998, the American Petroleum Institute proposed recruiting scientists to convince politicians, the media, and the public that climate science was too uncertain to justify environmental regulations.

In 1998, journalist Ross Gelbspan noted that his fellow journalists accepted that global warming was happening but were in "stage-two" denial of the climate crisis, unable to accept the feasibility of solutions. His book, Boiling Point, published in 2004, described the fossil-fuel industry's campaign to deny climate change and weaken public trust in climate science.

In Newsweek's August 2007 cover story "The Truth About Denial," Sharon Begley reported that "the denial machine is running at full throttle," and that this "well-coordinated, well-funded campaign" by scientists with opposing views, free-market think tanks, and industry had "created a paralyzing fog of doubt around climate change."

In 2006, George Monbiot wrote about the similarities between the methods used by groups funded by Exxon and those used by the tobacco company Philip Morris, including direct attacks on peer-reviewed science and attempts to create public controversy and doubt. They tried to prevent or delay regulation by creating doubt, manipulating debate, discrediting scientists, disputing their findings, and promoting claims that contradicted scientific research. This doubt protected the tobacco industry from legal action and regulation for many years.

For example, in 1992, an EPA report linked secondhand smoke to lung cancer. In response, the tobacco industry hired the public relations company APCO Worldwide, which developed a strategy of astroturfing campaigns to cast doubt on the science by linking smoking concerns with other issues, including global warming, in order to turn public opinion against calls for government action. The campaign portrayed public concerns as "unfounded fears" supposedly based only on "junk science" in contrast to their "sound science," and operated through front groups, mainly the Advancement of Sound Science Center (TASSC) and its Junk Science website, run by Steven Milloy. A tobacco company memo read, "Doubt is our product since it is the best means of competing with the 'body of fact' that exists in the mind of the general public. It is also the means of establishing a controversy."

Denial networks

The Paid Lobbyist (including the coal industry and others) is working to stop efforts to reduce emissions. The Don Quixote group includes emotionally committed individuals, often older people or some journalists, who strongly oppose climate action. The Eccentric Scientist group is small and rare. All three groups act like lobbyists by selecting a few research findings that support their views, even if they interpret the evidence in a way that favors their position.

A 2000 study showed that conservative think tanks were involved in spreading doubt about climate change. A 2008 study from the University of Central Florida found that 92% of U.S. literature questioning climate science was linked to conservative think tanks.

In 2013, the Center for Media and Democracy reported that the State Policy Network (SPN), which includes 64 U.S. think tanks, lobbied for major companies and conservative donors to oppose climate regulations.

Think tanks such as The Heritage Foundation, Marshall Institute, Cato Institute, and the American Enterprise Institute were important in trying to stop or remove environmental rules.

Between 2002 and 2010, 91 organizations working against climate action—think tanks, advocacy groups, and industry groups—had a total yearly income of about $900 million. During the same time, billionaires gave nearly $120 million secretly through the Donors Trust and Donors Capital Fund to more than 100 groups that aimed to weaken public trust in climate science.

In November 2021, a study by the Center for Countering Digital Hate identified ten groups responsible for nearly 70% of Facebook interactions with content denying climate change. Facebook said the study exaggerated the numbers and called it misleading.

The ten groups include Breitbart News, The Western Journal, Newsmax, Townhall, Media Research Center, The Washington Times, The Federalist, The Daily Wire, RT (TV network), and The Patriot Post.

Rebel Media and its leader, Ezra Levant, have spread climate change denial and promoted oil extraction in Alberta.

Willard Anthony Watts is an American blogger who runs a blog called Watts Up With That? that denies climate change.

A 2015 study found 4,556 people connected to 164 organizations that worked to downplay the dangers of climate change in the U.S.

In 2012, leaked documents showed The Heartland Institute was creating a school curriculum that presented climate change as a scientific debate. In 2017, a science education expert said the Heartland Institute’s materials contained errors, misleading claims, and incorrect information. The National Center for Science Education (NCSE) created classroom resources to counter these efforts.

In 2023, Republican politician and Baptist minister Mike Huckabee published Kids Guide to the Truth About Climate Change, which admits to global warming but downplays human causes. The book did not credit scientists or authors, and the NCSE called it "propaganda" and "unreliable." The book incorrectly stated that carbon dioxide levels were 280 parts per million, which was true in 391 BC but not in 2023, when levels were 420 parts per million.

In 2023, Florida approved a public school curriculum that included videos from the conservative group PragerU. These videos compared climate change skeptics to those who opposed Communism and Nazism, claimed renewable energy harms the environment, and said current warming is natural.

Texas, which influences many U.S. textbooks, proposed new editions in 2023 that included more information about the climate crisis. However, some books made it unclear that humans cause climate change and reduced the focus on fossil fuels. Texas Representative August Pfluger emphasized the importance of "secure, reliable energy" (oil and natural gas) from the Permian Basin. Pfluger’s website claimed that liquefied natural gas is "good for the economy and the environment."

Notable people who deny climate change

Over the next 400 years, sea levels are expected to rise by one-eighth of an inch. This change would slightly increase the amount of land near the ocean, such as beach areas.

Some people claim that climate change is a large-scale deception. They argue that predictions about climate change were made by individuals who do not believe their own countries can succeed. These individuals suggest that continuing to focus on reducing environmental harm could harm a nation’s future.

Politicians who acknowledge climate change but express doubt about human influence have been described as a type of climate denial. This approach is seen as a way to influence public opinion and delay action on climate issues.

In 2010, Donald Trump stated that the coldest winter on record and heavy snowfall along the coast showed that climate change predictions were incorrect. He claimed that efforts to reduce pollution, such as those proposed by Al Gore, would harm the U.S. manufacturing industry and benefit countries like China, Japan, and India. In 2012, Trump claimed that the idea of global warming was created to weaken U.S. manufacturing. By the early 2020s, his administration shifted from denying climate change to dismissing it, arguing that climate change should not be studied or addressed. In September 2025, Trump called United Nations climate predictions exaggerated and claimed that renewable energy sources like solar and wind power are unreliable and more expensive than fossil fuels.

In 2015, Senator Jim Inhofe, who chaired the Senate Committee on Environment and Public Works, said that the coldest winter in the western hemisphere contradicted claims of global warming. He attributed temperature changes to natural cycles, not human activity. However, he supported a Senate amendment stating that climate change is real and not a hoax. Inhofe later brought a snowball to the Senate floor to emphasize his belief that cold weather disproves global warming.

In 2017, former Senator Tom Coburn denied the scientific agreement that human activity causes global warming. He claimed that sea levels had risen by only 5 millimeters over 25 years and suggested that the world is experiencing global cooling. In 2013, he admitted he was a global warming denier.

Republican Jim Bridenstine, who became NASA administrator in 2018, initially claimed global temperatures were not rising. However, after being confirmed by the Senate, he acknowledged that human emissions of greenhouse gases are increasing global temperatures.

In 2018, Representative Mo Brooks claimed that rising sea levels are caused by coastal erosion and river silt, not melting glaciers.

In 2019, Brazil’s foreign minister, Ernesto Araújo, called global warming a plot by “cultural Marxists” and removed the government’s climate change division.

In April 2023, Representative Marjorie Taylor Greene called climate change a “scam” and claimed that fossil fuels are natural and beneficial. Her tweet included a chart that excluded carbon dioxide and methane, the two most significant greenhouse gases.

A 2024 study found that 23% of U.S. Congress members, all Republicans, deny climate change.

In July 2025, the U.S. Environmental Protection Agency announced plans to cancel a 2009 finding that greenhouse gases threaten public health. A review of the government’s report found at least 100 false or misleading statements. A scientific analysis published in September 2025 stated that the evidence of human-caused climate change harming health and welfare is clear and undisputed.

Kevin Trenberth, a climate scientist, has written extensively about climate change and challenged misinformation. He described interactions with scientists who question climate change, including Richard Lindzen, Roy Spencer, John Christy, and Pat Michaels.

Sherwood B. Idso, president of the Center for the Study of Carbon Dioxide and Global Change, argues that increased carbon dioxide is beneficial for crops and should not be restricted.

William M. Gray, a retired professor of atmospheric science, acknowledged global warming but claimed human activity contributes only slightly to it.

Frederick Seitz, a physicist and former president of the National Academy of Sciences, was involved in climate-related discussions.

Lobbying and related activities

Efforts to oppose environmental rules have included campaigns to create doubt about the science behind climate change and to hide the agreement among scientists and their data. These actions have reduced public trust in climate science.

By 2015, groups that denied climate change were most influential in the United States. These groups played a major role in the U.S. rejecting the Kyoto Protocol in 1997.

In what The Guardian described as "a recent example of limiting discussions about the climate crisis," the Trump administration in 2025 told employees of the U.S. Department of Energy to avoid using terms like "climate change," "decarbonization," "sustainable," "emissions," "green," "energy transition," "clean" or "dirty" energy, and "carbon/CO2 'footprint'." In January 2025, the Trump administration removed references to climate change and global heating from government websites and stopped many government programs focused on climate issues.

The fossil fuel industry has spent billions of dollars over many years to spread false information about climate change and question climate science. This campaign aimed to stop actions to address climate change and slow the move away from fossil fuels.

Research from Exxon’s archives at the University of Texas and interviews with former Exxon employees show that the company’s private scientific views and public statements about climate change were different. A review of Exxon’s climate models found that the company correctly predicted global warming in the late 1970s and early 1980s, correctly dismissed the idea of an upcoming ice age, and accurately estimated how much CO2 would cause dangerous warming.

From 1989 to 2002, the Global Climate Coalition, a group mostly made up of U.S. businesses, used strong lobbying and public relations tactics to block efforts to reduce greenhouse gas emissions and oppose the Kyoto Protocol. Companies and groups from the oil, coal, and auto industries funded the coalition. The New York Times reported that even as the coalition tried to make people doubt climate science, its own experts said the science about greenhouse gases and global warming could not be disproven. In 2000, Ford Motor Company was the first to leave the coalition due to pressure from environmental groups. Daimler-Chrysler, Texaco, the Southern Company, and General Motors later left the coalition. It shut down in 2002.

From January 2009 through June 2010, the oil, coal, and utility industries spent $500 million on lobbying efforts to stop climate change legislation.

A 2022 study traced the history of economic consultants hired by the petroleum industry from the 1990s to the 2010s. These consultants created models that exaggerated the costs of climate policies while ignoring their benefits. Their results were often presented to the public as independent research, even though they were funded by the industry. Their work helped block many major climate policies in the U.S. over decades. This study shows how the fossil fuel industry has supported biased economic studies to oppose climate action.

From the 1980s to the mid-2000s, ExxonMobil, an American oil and gas company, was a major force in denying climate change and opposing rules to reduce global warming. For example, ExxonMobil played a key role in stopping the U.S. from ratifying the Kyoto Protocol. The company supported groups that criticized the Kyoto Protocol and worked to weaken public understanding of the scientific agreement that burning fossil fuels causes global warming. Among major oil companies, ExxonMobil has been the most active in the climate change debate. A 2007 analysis by the Union of Concerned Scientists found that ExxonMobil used many of the same strategies, tactics, organizations, and people as the tobacco industry did when it denied the link between smoking and lung cancer.

ExxonMobil funded groups such as the Competitive Enterprise Institute, George C. Marshall Institute, Heartland Institute, the American Legislative Exchange Council, and the International Policy Network. Between 1998 and 2004, ExxonMobil gave $16 million to organizations that disputed the effects of global warming. From 1989 until April 2010, ExxonMobil and its earlier company, Mobil, regularly paid for advertisements in The New York Times, The Washington Post, and The Wall Street Journal that claimed the science of climate change was unclear.

A 2011 analysis by The Carbon Brief found that 9 out of 10 of the most frequent writers who cast doubt on climate change had ties to ExxonMobil. Greenpeace reported that Koch Industries spent over $50 million in the past 50 years to spread doubt about climate change.

Climate change deniers attacked the work of climate scientist Michael E. Mann for years. In February 2024, Mann won a $1 million judgment in a defamation lawsuit he filed in 2012 against bloggers who criticized his "hockey stick" graph showing temperature rises in the Northern Hemisphere. One of the bloggers called Mann’s work "fraudulent," even though multiple investigations had already cleared him of wrongdoing and supported his research.

After Elon Musk took over Twitter (now X) in 2022, key employees who promoted trustworthy content were removed, and climate scientists received more threatening, abusive, and harassing messages from deniers.

In 2023, reports showed an increase in climate change denial, especially among far-right groups. Deniers threatened meteorologists, accusing them of causing droughts, falsifying temperature readings, and selecting weather stations to misrepresent global warming. In 2023, CNN reported that meteorologists and climate communicators worldwide faced more harassment and false claims that they lied about or controlled the weather, inflated temperature records, or altered weather map colors to make climate change appear worse. Tagesschau, a German news service, called this a global issue.

In 2015, journalists reported that oil companies had known since the 1970s that burning oil and gas could cause climate change but continued to fund deniers for years.

Many large fossil fuel companies provide money to groups that try to make the public doubt the reliability of climate science. ExxonMobil and the Koch family foundations have been especially influential in funding climate change denial. The bankruptcy of the coal company Cloud Peak Energy revealed that it supported the Institute for Energy Research, a climate denial think tank, and other policy groups.

After the IPCC released its Fourth Assessment Report in 2007, the American Enterprise Institute (AEI) offered scientists from the U.S., Britain, and other countries $10,000 plus travel expenses to write articles critical of the report. AEI had received over $1.6 million from Exxon, and its vice chairman was Lee Raymond, a former Exxon leader. Raymond wrote letters claiming the IPCC report was not supported by scientific work. More than 20 AEI employees worked as consultants for the George W. Bush administration.

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Effects on public opinion

Media coverage about climate change influences how people feel about it. Campaigns that try to make people doubt climate science have led to fewer people believing in climate change. This has made it harder for laws to be passed to reduce CO2 emissions.

Climate change conspiracy theories and denial have led to weak or no action to stop the harm caused by global warming. Around 2017, about 40% of Americans thought climate change was a hoax, even though 100% of climate scientists, as of 2019, believed it was real.

A 2015 study found that people who heard about climate change conspiracy theories were less likely to take steps to reduce their carbon footprint than those who heard scientific facts.

Creating doubt about climate change, a common strategy used by deniers, has been very effective, especially in the U.S. This has led to low public concern and slow government action worldwide. A 2010 poll found that climate change skepticism was growing in the U.S., Canada, and the U.K. Possible reasons include focusing more on economic issues than environmental ones and negative views of the United Nations.

Tim Wirth said that climate change deniers used tactics similar to those of the tobacco industry. Both created doubt about science to influence the public and lawmakers. American media has often shown equal attention to climate change skeptics and scientists, even though most scientists agree on climate change. In 2006, Newsweek reported that most Europeans and Japanese accepted the scientific consensus on climate change, but only one-third of Americans believed human activity was a major cause.

Efforts by groups like the Western Fuels Association to confuse the public about climate change have been successful. This has been made worse by how media covers the topic. A 2012 poll found that 57% of Americans were unaware of or rejected the scientific agreement on climate change. Some groups claim scientists are no longer supporting climate change, but research shows 97% of scientific papers support the consensus, and this number is growing.

Some major oil companies now admit climate change exists but spend millions to delay or block climate policies.

Climate change denial has affected how scientists share information with the public. Michael E. Mann said that universities, scientific groups, and publishers often avoid defending science that powerful groups find threatening.

A study found that public support for climate policies and actions depends on people’s beliefs and how they see the risks. By March 2018, 95% of U.S. TV forecasters accepted that climate change is happening, and local TV stories about global warming had increased 15 times. Climate Central, which teaches meteorologists and provides TV graphics, has helped this change.

In the U.S., media often gives more attention to climate change skeptics than to scientists. This has not accurately shown how much scientists agree on climate change. In some cases, news outlets let skeptics explain climate science instead of experts. Media in the U.S. and U.K. differs from other countries, where reporting better matches scientific findings. Some journalists say this is because climate change denial is promoted in the U.S. by groups with business interests, using tactics similar to those of the tobacco industry.

Climate change denial is most common among white, politically conservative men in the U.S. In the U.S., France, and the U.K., climate change skeptics are more often featured in conservative news outlets, and their opinions are rarely challenged.

In 2018, the National Science Teachers Association told teachers to explain to students that there is no scientific debate about the basic facts of climate change.

Climate change denial has been supported by far-right political groups in Europe, such as Spain’s Vox, Finland’s Finns Party, Austria’s Freedom Party, and Germany’s Alternative for Deutschland (AfD). Russia spreads false information about climate change to blame Western countries.

In April 2023, French political scientist Jean-Yves Dormagen said that people with modest or conservative views were most skeptical about climate change. A study by the Jean-Jaurès Foundation in the same month compared climate skepticism to a new form of populism, with Steven E. Koonin as a representative.

Responses to denialism

Climate denial is not easily changed by logical arguments because it is not based on reason. Trying to correct denial by sharing facts or teaching science may not work. People who deny climate change often base their views on emotions, especially fears about things they are worried about.

Experts have said that fear of the solutions to climate change often causes people to oppose the science. Responding to these emotions, such as saying, "It can be painful to realize that our own lifestyles are responsible," may help move people from denial to acceptance and action.

Some people who once doubted climate change have changed their views. Ronald Bailey, who wrote a book about climate change in 2002, said in 2005 that people who still denied global warming should stop. By 2007, he agreed that the debate about whether humans cause global warming was over.

Jerry Taylor worked for groups that promoted climate denial for 20 years. He changed his mind after reading scientific evidence and now helps turn climate skeptics into activists. Michael Shermer, who publishes a science magazine, and journalist Gregg Easterbrook both changed their views in 2006 after seeing strong scientific evidence about human-caused global warming.

In 2009, Russian president Dmitri Medvedev said climate change was a trick to promote business. After wildfires in Russia in 2010, he admitted that the events showed climate change was real. Bob Inglis, a former U.S. representative, changed his mind in 2010 after his son and time with a climate scientist.

Richard A. Muller, a physics professor, once doubted climate science but later agreed that humans cause global warming. Conservative writer Max Boot, who once thought climate science was unclear, now says the evidence is clear.

Teaching people about how climate denial spreads—such as using false information or fake experts—can help people resist misinformation. Discussing how beliefs differ from scientific evidence may help people understand science better. Studies show that encouraging people to share their values before discussing climate science can improve dialogue.

A study in Australia found that farmers were less likely to deny climate change if they saw economic benefits from climate-friendly farming or if they had a younger person to take over their farm. In the U.S., rural climate dialogues helped neighbors work together on climate issues.

In 2013, Prince Charles compared the Earth to a dying patient, saying action must be taken without waiting for perfect evidence. As of February 2024, there are at least 32 lawsuits in the U.S. against fossil fuel companies for spreading climate denial. In June 2025, a UN report said climate misinformation is a major barrier to action and called for making it illegal to spread false climate information and banning fossil fuel lobbying and advertising.