• 21 Aug, 2019

• By, Wikipedia

Climate Science Denial

Climate change denial (also global warming denial) is a form of science denial characterized by rejecting, refusing to acknowledge, disputing, or fighting the scientific consensus on climate change. Those promoting denial commonly use rhetorical tactics to give the appearance of a scientific controversy where there is none. Climate change denial includes unreasonable doubts about the extent to which climate change is caused by humans, its effects on nature and human society, and the potential of adaptation to global warming by human actions. To a lesser extent, climate change denial can also be implicit when people accept the science but fail to reconcile it with their belief or action. Several studies have analyzed these positions as forms of denialism, pseudoscience, or propaganda.

Many issues that are settled in the scientific community, such as human responsibility for climate change, remain the subject of politically or economically motivated attempts to downplay, dismiss or deny them—an ideological phenomenon academics and scientists call climate change denial. Climate scientists, especially in the United States, have reported government and oil-industry pressure to censor or suppress their work and hide scientific data, with directives not to discuss the subject publicly. The fossil fuels lobby has been identified as overtly or covertly supporting efforts to undermine or discredit the scientific consensus on climate change.

Industrial, political and ideological interests organize activity to undermine public trust in climate science. Climate change denial has been associated with the fossil fuels lobby, the Koch brothers, industry advocates, ultraconservative think tanks, and ultraconservative alternative media, often in the U.S. More than 90% of papers that are skeptical of climate change originate from right-wing think tanks. Climate change denial is undermining efforts to act on or adapt to climate change, and exerts a powerful influence on the politics of climate change.

In the 1970s, oil companies published research that broadly concurred with the scientific community's view on climate change. Since then, for several decades, oil companies have been organizing a widespread and systematic climate change denial campaign to seed public disinformation, a strategy that has been compared to the tobacco industry's organized denial of the hazards of tobacco smoking. Some of the campaigns are even carried out by the same people who previously spread the tobacco industry's denialist propaganda.

Terminology

Climate change denial refers to denial, dismissal, or doubt of the scientific consensus on the rate and extent of climate change, its significance, or its connection to human behavior, in whole or in part. Climate denial is a form of science denial. It can also take pseudoscientific forms. The terms climate skeptics or contrarians are nowadays used with the same meaning as climate change deniers even though deniers usually prefer not to, in order to sow confusion as to their intentions.

The terminology is debated: most of those actively rejecting the scientific consensus use the terms skeptic and climate change skepticism, and only a few have expressed preference for being described as deniers. But the word "skepticism" is incorrectly used, as scientific skepticism is an intrinsic part of scientific methodology. In fact, all scientists adhere to scientific skepticism as part of the scientific process that demands continuing questioning. Both options are problematic, but climate change denial has become more widely used than skepticism.

The term contrarian is more specific but less frequently used. In academic literature and journalism, the terms climate change denial and climate change deniers have well-established usage as descriptive terms without any pejorative connotation.

The terminology evolved and emerged in the 1990s. By 1995 the word "skeptic" was being used specifically for the minority who publicized views contrary to the scientific consensus. This small group of scientists presented their views in public statements and the media rather than to the scientific community. Journalist Ross Gelbspan said in 1995 that industry had engaged "a small band of skeptics" to confuse public opinion in a "persistent and well-funded campaign of denial". His 1997 book The Heat is On may have been the first to concentrate specifically on the topic. In it, Gelbspan discusses a "pervasive denial of global warming" in a "persistent campaign of denial and suppression" involving "undisclosed funding of these 'greenhouse skeptics'" with "the climate skeptics" confusing the public and influencing decision makers.

In December 2014, an open letter from the Committee for Skeptical Inquiry called on the media to stop using the term skepticism when referring to climate change denial. It contrasted scientific skepticism—which is "foundational to the scientific method"—with denial—"the a priori rejection of ideas without objective consideration"—and the behavior of those involved in political attempts to undermine climate science. It said: "Not all individuals who call themselves climate change skeptics are deniers. But virtually all deniers have falsely branded themselves as skeptics. By perpetrating this misnomer, journalists have granted undeserved credibility to those who reject science and scientific inquiry."

In 2015, The New York Times's public editor said that the Times was increasingly using denier when "someone is challenging established science", but assessing this on an individual basis with no fixed policy, and would not use the term when someone was "kind of wishy-washy on the subject or in the middle". The executive director of the Society of Environmental Journalists said that while there was reasonable skepticism about specific issues, she felt that "denier" was "the most accurate term when someone claims there is no such thing as global warming, or agrees that it exists but denies that it has any cause we could understand or any impact that could be measured".

A petition by climatetruth.org asked signers to "Tell the Associated Press: Establish a rule in the AP Stylebook ruling out the use of 'skeptic' to describe those who deny scientific facts". In September 2015, the Associated Press announced "an addition to AP Stylebook entry on global warming" that advised "to describe those who don't accept climate science or dispute the world is warming from human-made forces, use 'climate change doubters' or 'those who reject mainstream climate science'. Avoid use of 'skeptics' or 'deniers'". In May 2019, The Guardian also rejected use of the term "climate skeptic" in favor of "climate science denier".

In addition to explicit denial, people have also shown implicit denial by accepting the scientific consensus but failing to "translate their acceptance into action". This type of denial is also called soft climate change denial.

Categories and tactics

In 2004, German climate scientist Stefan Rahmstorf described how the media give the misleading impression that climate change is still disputed within the scientific community, attributing this impression to climate change skeptics' PR efforts. He identified different positions that climate skeptics argue, which he used as a taxonomy of climate change skepticism. Later the model was also applied to denial:

1. Trend skeptics or deniers (who claim that no significant warming is taking place): "Given that the warming is now evident even to laypeople, the trend skeptics are a gradually vanishing breed. They [...] claim that the warming trend measured by weather stations is an artefact due to urbanisation around those stations (urban heat island effect)."
2. Attribution skeptics or deniers (who accept the climate change trends but claim there are natural causes for this, not human-made ones): "A few of them even deny that the rise in the atmospheric CO₂ content is anthropogenic; they claim that the atmospheric CO₂ is released from the ocean by natural processes."
3. Impact skeptics or deniers (who think climate change is harmless or even beneficial, for example the "potential extension of agriculture into higher latitudes").
4. Sometimes consensus denial is added, for people who question the existence of the scientific consensus on anthropogenic climate change.

The National Center for Science Education describes climate change denial as disputing differing points in the scientific consensus, a sequential range of arguments from denying the occurrence of climate change, accepting that but denying any significant human contribution, accepting these but denying scientific findings on how this would affect nature and human society, to accepting all these but denying that humans can mitigate or reduce the problems. James L. Powell provides a more extended list, as does climatologist Michael E. Mann in "six stages of denial", a ladder model whereby deniers have over time conceded acceptance of points, while retreating to a position that still rejects the mainstream consensus:

1. CO₂ is not actually increasing.
2. Even if it is, the increase has no impact on the climate since there is no convincing evidence of warming.
3. Even if there is warming, it is due to natural causes.
4. Even if the warming cannot be explained by natural causes, the human impact is small, and the impact of continued greenhouse gas emissions will be minor.
5. Even if the current and future projected human effects on Earth's climate are not negligible, the changes are generally going to be good for us.
6. Whether or not the changes are going to be good for us, humans are very adept at adapting to changes; besides, it's too late to do anything about it, and/or a technological fix is bound to come along when we really need it.

Climate change denial is a form of denialism. Chris and Mark Hoofnagle have defined denialism in this context as the use of rhetorical devices "to give the appearance of legitimate debate where there is none, an approach that has the ultimate goal of rejecting a proposition on which a scientific consensus exists." This process characteristically uses one or more of the following tactics:

1. Allegations that scientific consensus involves conspiring to fake data or suppress the truth: a climate change conspiracy theory.
2. Fake experts, or individuals with views at odds with established knowledge, at the same time marginalizing or denigrating published topic experts. Like the manufactured doubt over smoking and health, a few contrarian scientists oppose the climate consensus, some of them the same people.
3. Selectivity, such as cherry-picking atypical or even obsolete papers, in the same way that the MMR vaccine controversy was based on one paper: examples include discredited ideas of the medieval warm period.
4. Unworkable demands of research, claiming that any uncertainty invalidates the field or exaggerating uncertainty while rejecting probabilities and mathematical models.
5. Logical fallacies.

Discussing specific aspects of climate change science

Further information: History of climate change science § Discredited theories and reconciled apparent discrepancies

Some politicians and climate change denial groups say that because CO₂ is only a trace gas in the atmosphere (0.04%), it cannot cause climate change. But scientists have known for over a century that even this small proportion has a significant warming effect, and doubling the proportion leads to a large temperature increase. Some groups allege that water vapor is a more significant greenhouse gas, and is left out of many climate models. But while water vapor is a greenhouse gas, its very short atmospheric lifetime (about 10 days) compared to that of CO₂ (hundreds of years) means that CO₂ is the primary driver of increasing temperatures; water vapor acts as a feedback, not a forcing, mechanism.

Climate denial groups may also argue that global warming has stopped, that a global warming hiatus is in effect, or that global temperatures are actually decreasing, leading to global cooling. These arguments are based on short-term fluctuations and ignore the long-term pattern.

Some groups and prominent deniers such as William Happer argue that there is a greenhouse gas saturation effect that significantly decreases the warming potential of further gases released into the atmosphere. Such an effect does exist in some form, as Happer's research demonstrates, but is likely negligible with respect to net global warming.

Climate change denial literature often features the suggestion that we should wait for better technologies before addressing climate change, when they will be more affordable and effective.

Playing up the potential non-human causes

Further information: History of climate change science § Solar variation

Climate denial groups often point to natural variability, such as sunspots and cosmic rays, to explain the warming trend. According to these groups, there is natural variability that will abate over time, and human influence has little to do with it. But climate models already take these factors into account. The scientific consensus is that they cannot explain the observed warming trend.

Playing up flawed studies

In 2007, the Heartland Institute published an article titled "500 Scientists Whose Research Contradicts Man-Made Global Warming Scares" by Dennis T. Avery, a food policy analyst at the Hudson Institute. Avery's list was immediately called into question for misunderstanding and distorting the conclusions of many of the named studies and citing outdated, flawed studies that had long been abandoned. Many of the scientists on the list demanded their names be removed. At least 45 of them had no idea they were included as "co-authors" and disagreed with the article's conclusions. The Heartland Institute refused these requests, saying that the scientists "have no right—legally or ethically—to demand that their names be removed from a bibliography composed by researchers with whom they disagree".

Disputing IPCC reports and processes

Further information: Intergovernmental Panel on Climate Change § Challenges and controversies

Deniers have generally attacked either the IPCC's processes, scientist or the synthesis and executive summaries; the full reports attract less attention.

In 1996, climate change denier Frederick Seitz criticized the 1995 IPCC Second Assessment Report, alleging corruption in the peer-review process. Scientists rejected his assertions; the presidents of the American Meteorological Society and University Corporation for Atmospheric Research described his claims as part of a "systematic effort by some individuals to undermine and discredit the scientific process".

In 2005, the House of Lords Economics Committee wrote, "We have some concerns about the objectivity of the IPCC process, with some of its emissions scenarios and summary documentation apparently influenced by political considerations." It doubted the high emission scenarios and said that the IPCC had "played-down" what the committee called "some positive aspects of global warming". The main statements of the House of Lords Economics Committee were rejected in the response made by the United Kingdom government.

On 10 December 2008, the U.S. Senate Committee on Environment and Public Works minority members released a report under the leadership of the Senate's most vocal global warming denier, Jim Inhofe. It says it summarizes scientific dissent from the IPCC. Many of its statements about the numbers of people listed in the report, whether they are actually scientists, and whether they support the positions attributed to them, have been disputed. Inhofe also said that "some parts of the IPCC process resembled a Soviet-style trial, in which the facts are predetermined, and ideological purity trumps technical and scientific rigor."

Creating doubts about scientific publishing processes

For broader coverage of this topic, see Conflicts of interest in academic publishing.

Some climate change deniers promote conspiracy theories alleging that the scientific consensus is illusory, or that climatologists are acting out of their own financial interests by causing undue alarm about a changing climate. Some climate change deniers claim that there is no scientific consensus on climate change, that any evidence for a scientific consensus is faked, or that the peer-review process for climate science papers has become corrupted by scientists seeking to suppress dissent. No evidence of such conspiracies has been presented. In fact, much of the data used in climate science is publicly available, contradicting allegations that scientists are hiding data or stonewalling requests.

Some climate change deniers assert that the scientific consensus on climate change is based on conspiracies to produce manipulated data or suppress dissent. It is one of a number of tactics used in climate change denial to attempt to manufacture political and public controversy disputing this consensus. These people typically allege that, through worldwide acts of professional and criminal misconduct, the science behind climate change has been invented or distorted for ideological or financial reasons. They promote harmful conspiracy theories alleging that scientists and institutions involved in global warming research are part of a global scientific conspiracy or engaged in a manipulative hoax.

The Great Global Warming Swindle is a 2007 British polemical documentary film directed by Martin Durkin that denies the scientific consensus about the reality and causes of climate change, justifying this by suggesting that climatology is influenced by funding and political factors. The film strongly opposes the scientific consensus on climate change. It argues that the consensus on climate change is the product of "a multibillion-dollar worldwide industry: created by fanatically anti-industrial environmentalists; supported by scientists peddling scare stories to chase funding; and propped up by complicit politicians and the media". The programme's publicity materials claim that man-made global warming is "a lie" and "the biggest scam of modern times." The film received strong criticism from many scientists and others. Journalist George Monbiot called it "the same old conspiracy theory that we've been hearing from the denial industry for the past ten years".

The climate deniers involved in the Climatic Research Unit email controversy ("Climategate") in 2009 claimed that researchers faked the data in their research publications and suppressed their critics in order to receive more funding (i.e. taxpayer money). Eight committees investigated these allegations and published reports, each finding no evidence of fraud or scientific misconduct. According to the Muir Russell report, the scientists' "rigor and honesty as scientists are not in doubt", the investigators "did not find any evidence of behavior that might undermine the conclusions of the IPCC assessments", but there had been "a consistent pattern of failing to display the proper degree of openness." The scientific consensus that climate change is occurring as a result of human activity remained unchanged at the end of the investigations.

Being "lukewarm" or "skeptical"

In 2012, Clive Hamilton published the essay "Climate change and the soothing message of luke-warmism". He defined luke-warmists as "those who appear to accept the body of climate science but interpret it in a way that is least threatening: emphasising uncertainties, playing down dangers, and advocating a slow and cautious response. They are politically conservative and anxious about the threat to the social structure posed by the implications of climate science. Their 'pragmatic' approach is therefore alluring to political leaders looking for a justification for policy minimalism." He cited Ted Nordhaus and Michael Shellenberger of the Breakthrough Institute, and also Roger A. Pielke Jr., Daniel Sarewitz, Steve Rayner, Mike Hulme and "the pre-eminent luke-warmist" Danish economist Bjørn Lomborg.

Climate change skepticism, while in some cases professing to do research on climate change, has focused instead on influencing the opinion of the public, legislators and the media, in contrast to legitimate science.

Pope Francis groups together four types of respondents rejecting climate change: those who "deny, conceal, gloss over or relativize the issue".

Pushing for adaptation only

For broader coverage of this topic, see Climate change adaptation.

The conservative National Center for Policy Analysis, whose "Environmental Task Force" contains a number of climate change deniers, including Sherwood Idso and S. Fred Singer, has said, "The growing consensus on climate change policies is that adaptation will protect present and future generations from climate-sensitive risks far more than efforts to restrict CO₂ emissions."

The adaptation-only plan is also endorsed by oil companies like ExxonMobil. According to a Ceres report, "ExxonMobil's plan appears to be to stay the course and try to adjust when changes occur. The company's plan is one that involves adaptation, as opposed to leadership."

The George W. Bush administration also voiced support for an adaptation-only policy in 2002. "In a stark shift for the Bush administration, the United States has sent a climate report [U.S. Climate Action Report 2002] to the United Nations detailing specific and far-reaching effects it says global warming will inflict on the American environment. In the report, the administration also for the first time places most of the blame for recent global warming on human actions—mainly the burning of fossil fuels that send heat-trapping greenhouse gases into the atmosphere." The report "does not propose any major shift in the administration's policy on greenhouse gases. Instead it recommends adapting to inevitable changes instead of making rapid and drastic reductions in greenhouse gases to limit warming." This position apparently precipitated a similar shift in emphasis at the COP 8 climate talks in New Delhi several months later; "The shift satisfies the Bush administration, which has fought to avoid mandatory cuts in emissions for fear it would harm the economy. 'We're welcoming a focus on more of a balance on adaptation versus mitigation', said a senior American negotiator in New Delhi. 'You don't have enough money to do everything.'"

Some find this shift and attitude disingenuous and indicative of a bias against prevention (i.e. reducing emissions/consumption) and toward prolonging the oil industry's profits at the environment's expense. In an article addressing the supposed economic hazards of addressing climate change, writer and environmental activist George Monbiot wrote: "Now that the dismissal of climate change is no longer fashionable, the professional deniers are trying another means of stopping us from taking action. It would be cheaper, they say, to wait for the impacts of climate change and then adapt to them".

Delaying climate change mitigation measures

Further information: Economics of climate change mitigation and Economic analysis of climate change

Climate change deniers often debate whether action (such as the restrictions on the use of fossil fuels to reduce carbon-dioxide emissions) should be taken now or in the near future. They fear the economic ramifications of such restrictions. For example, in a 1998 speech, a staff member of the Cato Institute, a libertarian think tank, argued that emission controls' negative economic effects outweighed their environmental benefits. Climate change deniers tend to argue that even if global warming is caused solely by the burning of fossil fuels, restricting their use would damage the world economy more than the increases in global temperature.

Conversely, the general consensus is that early action to reduce emissions would help avoid much greater economic costs later, and reduce the risk of catastrophic, irreversible change.

Earlier, climate change deniers' online YouTube content focused on denying global warming, or saying such warming is not caused by humans burning fossil fuel. As such denials became untenable, content shifted to asserting that climate solutions are unworkable, that global warming is harmless or even beneficial, and that the environmental movement is unreliable.

A 2016 article in Science made the case that opposition to climate policy was beginning to take a "rhetorical shift away from outright skepticism" and called this neoskepticism. Rather than denying the existence of global warming, neoskeptics instead "question the magnitude of the risks and assert that reducing them has more costs than benefits." According to the authors, the emergence of neoskepticism "heightens the need for science to inform decision making under uncertainty and to improve communication and education."

There is a range of possible mitigation policies. Disagreement over the sufficiency, viability, or desirability of a given policy is not necessarily neoskepticism. But neoskepticism is marked by failure to appreciate the increased risks associated with delayed action. Gavin Schmidt has called neoskepticism a form of confirmation bias and the tendency to always take "as gospel the lowest estimate of a plausible range". Neoskeptics err on the side of the least disruptive projections and least active policies and, as such, neglect or misapprehend the full spectrum of risks associated with global warming.

In political terms, soft climate denial can stem from concerns about the economics and economic impacts of climate change, particularly the concern that strong measures to combat global warming or mitigate its impacts will seriously inhibit economic growth.

Climate change denial is commonly rooted in a phenomenon known as conspiracy theory, in which people misattribute events to a powerful group's secret plot or plan. People with certain cognitive tendencies are also more drawn than others to conspiracy theories about climate change. Conspiratorial beliefs are more predominantly found in narcissistic people and those who consistently look for meanings or patterns in their world, including believers in paranormal activity. Climate change conspiracy disbelief is also linked to lower levels of education and analytic thinking.

Scientists are investigating which factors associated with conspiracy belief can be influenced and changed. They have identified "uncertainty, feelings of powerlessness, political cynicism, magical thinking, and errors in logical and probabilistic reasoning".

In 2012, researchers found that belief in other conspiracy theories was associated with being more likely to endorse climate change denial. Examples of science-related conspiracy theories that some people believe include that aliens exist, childhood vaccines are linked to autism, Bigfoot is real, the government "adds fluoride to drinking water for 'sinister' purposes", and the moon landing was faked.

Examples of alleged climate change conspiracies include:

• Aiming at New World Order: Senator James Inhofe, a Republican from Oklahoma, suggested in 2006 that supporters of the Kyoto Protocol such as Jacques Chirac are aiming at global governance. In his speech, Inhofe said: "So, I wonder: are the French going to be dictating U.S. policy?" William M. Gray also claimed in 2006 that scientists support the scientific consensus on climate change because they were promoted by government leaders and environmentalists seeking world government. He added that its purpose was to exercise political influence, to try to introduce world government, and to control people.
• To promote other types of energy sources: Some have claimed that the "threat of global warming is an attempt to promote nuclear power". Another claim is that "because many people have invested in renewable energy companies, they stand to lose a lot of money if global warming is shown to be a myth. According to this theory, environmental groups therefore bribe climate scientists to doctor their data so that they are able to secure their financial investment in green energy."

A study published in PLOS One in 2024 found that even a single repetition of a claim was sufficient to increase the perceived truth of both climate science-aligned claims and climate change skeptic/denial claims—"highlighting the insidious effect of repetition". This effect was found even among climate science endorsers.

Many of the climate change deniers have disagreed, in whole or part, with the scientific consensus regarding other issues, particularly those relating to environmental risks, such as ozone depletion, DDT, and passive smoking.

In the 1990s, the Marshall Institute began campaigning against increased regulations on environmental issues such as acid rain, ozone depletion, second-hand smoke, and the dangers of DDT. In each case their argument was that the science was too uncertain to justify any government intervention, a strategy it borrowed from earlier efforts to downplay the health effects of tobacco in the 1980s. This campaign would continue for the next two decades.

In 2023, an increase in climate change denial was noted, particularly among supporters of the far right.

It has been suggested that climate change can conflict with a nationalistic view because it is "unsolvable" at the national level and requires collective action between nations or between local communities, and that therefore populist nationalism tends to reject the science of climate change.

The UK Independence Party's policy on climate change has been influenced by climate change denier Christopher Monckton and by its energy spokesman Roger Helmer, who has said, "It is not clear that the rise in atmospheric CO₂ is anthropogenic."

Jerry Taylor of the Niskanen Center posits that climate change denial is an important component of Trumpian historical consciousness, and "plays a significant role in the architecture of Trumpism as a developing philosophical system".

Though climate change denial was apparently waning circa 2021, some right-wing nationalist organizations have adopted a theory of "environmental populism" advocating that natural resources be preserved for a nation's existing residents, to the exclusion of immigrants. Other such right-wing organizations have contrived new "green wings" that falsely assert that refugees from poor nations cause environmental pollution and climate change and should therefore be excluded.

A study published in PLOS Climate studied two forms of national identity—defensive or "national narcissism" and "secure national identification"—for their correlation to support for policies to mitigate climate change and transition to renewable energy. The authors defined national narcissism as "a belief that one's national group is exceptional and deserves external recognition underlain by unsatisfied psychological needs". They defined secure national identification as "reflect[ing] feelings of strong bonds and solidarity with one's ingroup members, and sense of satisfaction in group membership". The researchers concluded that secure national identification tends to support policies promoting renewable energy, while national narcissism is inversely correlated with support for such policies—except to the extent that such policies, as well as greenwashing, enhance the national image. Right-wing political orientation, which may indicate susceptibility to climate conspiracy beliefs, was also found to be negatively correlated with support for genuine climate mitigation policies.

One worldview that often leads to climate change denial is belief in free enterprise capitalism. The "freedom of the commons" (tragedy of the commons), or the freedom to use natural resources as a public good as it is practiced in free enterprise capitalism, destroys important ecosystems and their functions, and so having a stake in this worldview does not correlate with climate change mitigation behavior. Political worldview plays an important role in environmental policy and action. Liberals tend to focus on environmental risks, while conservatives focus on the benefits of economic development. Because of this difference, conflicting opinions on the acceptance of climate change arise.

A study of climate change denial indicators in public opinion data from ten Gallup surveys from 2001 to 2010 shows that conservative white men in the U.S. are significantly more likely to deny climate change than other Americans. Conservative white men who report understanding climate change very well are even more likely to deny climate change.

Another reason for the discrepancy in climate change denial between liberals and conservatives is that "contemporary environmental discourse is based largely on moral concerns related to harm and care, which are more deeply held by liberals than by conservatives"; if the discourse is instead framed using moral concerns related to purity that are more deeply held by conservatives, the discrepancy is resolved.

In the U.S., climate change denial largely correlates with political affiliation. This is partially because Democrats focus more on tighter government regulations and taxation, which are the basis for most environmental policy. Political affiliation also affects how different people interpret the same facts. More highly educated people are less likely to rely on their own interpretation and political ideology rather than on scientists' opinions. Therefore, political worldviews override expert opinion on the interpretation of climate facts and evidence of anthropogenic climate change.

Affiliation with a political group, especially in the U.S., is an important personal and social identity for many. Because of this, many people hold the popular values of their political affiliation, regardless of their personal beliefs, so as not to be ostracized by the group.

The examples and perspective in this section may not represent a worldwide view of the subject. You may improve this section, discuss the issue on the talk page, or create a new section, as appropriate. (February 2024) (Learn how and when to remove this message)

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 its finding that if then prevailing trends of coal consumption continued, "the temperature of the earth's atmosphere will increase" and "vast changes in the climates of the earth will result. [...] Such changes in temperature will cause melting of the polar icecaps, which, in turn, would result in the inundation of many coastal cities, including New York and London." In a discussion following this paper in the same publication, a combustion engineer for Peabody Coal, now Peabody Energy, the world's largest coal supplier, added that the coal industry was merely "buying time" before additional government air pollution regulations would be promulgated to clean the air. Nevertheless, the coal industry publicly advocated for decades thereafter the position that increased carbon dioxide in the atmosphere is beneficial for the planet.

In response to increasing public awareness of the greenhouse effect in the 1970s, conservative reaction built up, denying environmental concerns that could lead to government regulation. In 1977, the first Secretary of Energy, James Schlesinger, suggested President Jimmy Carter take no action regarding a climate change memo, citing uncertainty. During the presidency of Ronald Reagan, global warming became a political issue, with immediate plans to cut spending on environmental research, particularly climate-related, and stop funding for CO₂ monitoring. Congressman Al Gore was aware of the developing science: he joined others in arranging congressional hearings from 1981 onward, with testimony from scientists including Revelle, Stephen Schneider, and Wallace Smith Broecker.

An Environmental Protection Agency (EPA) report in 1983 said global warming was "not a theoretical problem but a threat whose effects will be felt within a few years", with potentially "catastrophic" consequences. The Reagan administration called the report "alarmist" and the dispute was widely covered. Public attention turned to other issues, then the 1985 finding of a polar ozone hole brought a swift international response. To the public, this was related to climate change and the possibility of effective action, but news interest faded.

Public attention was renewed amid summer droughts and heat waves when James Hansen testified to a Congressional hearing on 23 June 1988, saying with high confidence that long-term warming was underway with severe warming likely within the next 50 years, and warning of likely storms and floods. There was increasing media attention: the scientific community had reached a broad consensus that the climate was warming, human activity was very likely the primary cause, and there would be significant consequences if the trend was not curbed. These facts encouraged discussion about new environmental regulations, which the fossil fuel industry opposed.

From 1989 onward, industry-funded organizations, including the Global Climate Coalition and the George C. Marshall Institute, sought to spread doubt, in a strategy already developed by the tobacco industry. A small group of scientists opposed to the consensus on global warming became politically involved, and with support from conservative political interests, began publishing in books and the press rather than in scientific journals. Historian Spencer Weart identifies this period as the point where skepticism about basic aspects of climate science was no longer justified, and those spreading mistrust about these issues became deniers. As the scientific community and new data increasingly refuted their arguments, deniers turned to political arguments, making personal attacks on scientists' reputations, and promoting ideas of global warming conspiracies.

With the 1989 fall of communism, the attention of U.S. conservative think tanks, which had been organized in the 1970s as an intellectual counter-movement to socialism, turned from the "red scare" to the "green scare" tactic, which they saw as a threat to their aims of private property, free trade market economies, and global capitalism. They used environmental skepticism to promote denial of environmental problems such as loss of biodiversity and climate change.

The campaign to spread doubt continued into the 1990s, including an advertising campaign funded by coal industry advocates intended to "reposition global warming as theory rather than fact". There was also a 1998 proposal by the American Petroleum Institute to recruit scientists to convince politicians, the media, and the public that climate science was too uncertain to warrant environmental regulation.

In 1998, journalists Ross Gelbspan noted that his fellow journalists accepted that global warming was occurring, but were in "'stage-two' denial of the climate crisis", unable to accept the feasibility of solutions to the problem. His book, Boiling Point, published in 2004, detailed the fossil-fuel industry's campaign to deny climate change and undermine public confidence 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 contrarian scientists, free-market think tanks, and industry had "created a paralyzing fog of doubt around climate change."

In 2006, George Monbiot published an article about similarities between the methods of groups funded by Exxon and those of the tobacco giant Philip Morris, including direct attacks on peer-reviewed science and attempts to create public controversy and doubt.

The approach to downplay climate change's significance was copied from tobacco lobbyists, who attempted to prevent or delay the introduction of regulation in the face of scientific evidence linking tobacco to lung cancer. They attempted to discredit the research by creating doubt, manipulating debate, discrediting the scientists involved, disputing their findings, and creating and maintaining an apparent controversy by promoting claims that contradicted scientific research. Doubt shielded the tobacco industry from litigation and regulation for decades.

For example, in 1992 an EPA report linked secondhand smoke with lung cancer. In response, the tobacco industry engaged the APCO Worldwide public relations company, which set out a strategy of astroturfing campaigns to cast doubt on the science by linking smoking anxieties with other issues, including global warming, in order to turn public opinion against calls for government intervention. The campaign depicted public concerns as "unfounded fears" supposedly based only on "junk science" in contrast to their "sound science", and operated through front groups, primarily 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."

During the 1990s, the tobacco campaign died away, and TASSC began taking funding from oil companies, including Exxon. Its website became central in distributing "almost every kind of climate-change denial that has found its way into the popular press." Monbiot wrote that TASSC "has done more damage to the campaign to halt [climate change] than any other body" by trying to manufacture the appearance of a grassroots movement against "unfounded fear" and "over-regulation".

The Republican Party in the United States is unique in denying anthropogenic climate change among conservative political parties in the Western world. In 1994, according to a leaked memo, the Republican strategist Frank Luntz advised members of the Republican Party, with regard to climate change, that "you need to continue to make the lack of scientific certainty a primary issue" and "challenge the science" by "recruiting experts who are sympathetic to your view". (In 2006, Luntz said he still believes "back [in] '97, '98, the science was uncertain", but now agreed with the scientific consensus.) From 2008 to 2017, the Republican Party went from "debating how to combat human-caused climate change to arguing that it does not exist". In 2011, "more than half of the Republicans in the House and three-quarters of Republican senators" said "that the threat of global warming, as a human-made and highly threatening phenomenon, is at best an exaggeration and at worst an utter 'hoax'".

In 2014, more than 55% of congressional Republicans were reported to be climate change deniers. According to PolitiFact in May 2014, Jerry Brown's statement that "virtually no Republican" in Washington accepts climate change science was "mostly true"; PolitiFact counted "eight out of 278, or about 3 percent" of Republican members of Congress who "accept the prevailing scientific conclusion that global warming is both real and man-made."

In 2005, The New York Times reported that Philip Cooney, a former fossil fuel lobbyist and "climate team leader" at the American Petroleum Institute and President George W. Bush's chief of staff of the Council on Environmental Quality, had "repeatedly edited government climate reports in ways that play down links between such emissions and global warming, according to internal documents". Sharon Begley reported in Newsweek that Cooney "edited a 2002 report on climate science by sprinkling it with phrases such as 'lack of understanding' and 'considerable uncertainty'." Cooney reportedly removed an entire section on climate in one report, whereupon another lobbyist sent him a fax saying "You are doing a great job."

In the 2016 U.S. election cycle, every Republican presidential candidate, and the Republican leader in the U.S. Senate, questioned or denied climate change, and opposed U.S. government steps to address it.

In 2016, Aaron McCright argued that anti-environmentalism—and climate change denial specifically—had expanded in the U.S. to become "a central tenet of the current conservative and Republican identity".

In a 2017 interview, United States Secretary of Energy Rick Perry acknowledged the existence of climate change and impact from humans, but said that he did not agree that carbon dioxide was its primary driver, pointing instead to "the ocean waters and this environment that we live in". The American Meteorological Society responded in a letter to Perry that it is "critically important that you understand that emissions of carbon dioxide and other greenhouse gases are the primary cause", pointing to conclusions of scientists worldwide.

Climate denial has started to decrease among the Republican Party leadership toward acknowledgment that "the climate is changing"; a 2019 study by several major think tanks called the climate right "fragmented and underfunded".

Florida Republican Tom Lee described people's emotional impact and reactions to climate change, saying: "I mean, you have to be the Grim Reaper of reality in a world that isn't real fond of the Grim Reaper. That's why I use the term 'emotionally shut down', because I think I think you lose people at hello a lot times in the Republican conversation over this."

When a moderator at the August 23, 2023, Republican presidential debate asked the candidates to raise their hands if they believed human behavior is causing climate change, none did. Entrepreneur Vivek Ramaswamy said, "the climate change agenda is a hoax" and that "more people are dying of climate change policies than they actually are of climate change"; none of his competitors challenged him directly on climate. After investigating Ramaswamy's latter claim, a Washington Post fact check found no supporting evidence.

A 2000 article explored the connection between conservative think tanks and climate change denial. Research found that specific groups were marshaling skepticism against climate change; a 2008 University of Central Florida study found that 92% of "environmentally skeptical" literature published in the U.S. was partly or wholly affiliated with self-proclaimed conservative think tanks.

In 2013, the Center for Media and Democracy reported that the State Policy Network (SPN), an umbrella group of 64 U.S. think tanks, had been lobbying on behalf of major corporations and conservative donors to oppose climate change regulation.

Conservative and libertarian think tanks in the U.S., such as The Heritage Foundation, Marshall Institute, Cato Institute, and the American Enterprise Institute, were significant participants in lobbying attempts seeking to halt or eliminate environmental regulations.

Between 2002 and 2010, the combined annual income of 91 climate change counter-movement organizations—think tanks, advocacy groups and industry associations—was roughly $900 million. During the same period, billionaires secretively donated nearly $120 million (£77 million) via the Donors Trust and Donors Capital Fund to more than 100 organizations seeking to undermine the public perception of the science on climate change.

In November 2021, a study by the Center for Countering Digital Hate identified "ten fringe publishers" that together were responsible for nearly 70 percent of Facebook user interactions with content that denied climate change. Facebook said the percentage was overstated and called the study misleading.

The "toxic ten" publishers: 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.

The Rebel Media and its director, Ezra Levant, have promoted climate change denial and oil sands extraction in Alberta.

Willard Anthony Watts is an American blogger who runs Watts Up With That?, a climate change denial blog.

A piece of research from 2015 identified 4,556 people with overlapping network ties to 164 organizations that were responsible for most efforts to downplay the threat of climate change in the U.S.

According to documents leaked in February 2012, The Heartland Institute is developing a curriculum for use in schools that frames climate change as a scientific controversy. In 2017, deputy director of the National Center for Science Education (NCSE) Glenn Branch wrote, "the Heartland Institute is continuing to inflict its climate change denial literature on science teachers across the country". Each significant claim was rated for accuracy by scientists who were experts on that topic. It was found that "the 'Key Findings' section are incorrect, misleading, based on flawed logic, or simply factually inaccurate". The NCSE has prepared Classroom Resources in response to Heartland and other anti-science threats.

In 2023, Republican politician and Baptist minister Mike Huckabee published Kids Guide to the Truth About Climate Change, which acknowledges global warming but minimizes the influence of human emissions. Marketed as an alternative to mainstream education, the publication does not attribute authorship or cite scientific credentials. The NCSE's deputy director called the publication "propaganda" and "very unreliable as a guide to climate change for kids", saying it represented "present-day" atmospheric concentrations of carbon dioxide as 280 parts per million (ppm), which was true in 391 BC but short of 2023's actual concentration of 420 ppm.

In 2023, the state of Florida approved a public school curriculum including videos produced by conservative advocacy group PragerU that liken climate change skeptics to those who fought Communism and Nazism, imply renewable energy harms the environment, and say current global warming occurs naturally.

Texas, which has a large influence on school textbooks published nationwide, proposed textbooks in 2023 that included more information about the climate crisis than editions a decade earlier. But some books clouded the human causes of climate change and downplayed the role of fossil fuels, with Texas U.S. Representative August Pfluger emphasizing the importance of "secure, reliable energy" (oil and natural gas) produced in the Permian Basin. In September 2023, Pfluger's Congressional website said, "we cannot allow the radical climate lobby to infiltrate Texas middle schools and brainwash our children", claiming that liquefied natural gas is "not only...good for our economy, but it's good for the environment".

Acknowledgment of climate change by politicians, while expressing uncertainty as to how much of it is due to human activity, has been described as a new form of climate denial, and "a reliable tool to manipulate public perception of climate change and stall political action".

Former U.S. Senator Tom Coburn in 2017 discussed the Paris agreement and denied the scientific consensus on human-caused global warming. Coburn claimed that sea level rise had been no more than 5 mm in 25 years, and asserted there was now global cooling. In 2013, he said, "I am a global warming denier. I don't deny that."

In 2010, Donald Trump (who later became president of the United States from 2017 to 2021) said, "With the coldest winter ever recorded, with snow setting record levels up and down the coast, the Nobel committee should take the Nobel Prize back from Al Gore....Gore wants us to clean up our factories and plants in order to protect us from global warming, when China and other countries couldn't care less. It would make us totally noncompetitive in the manufacturing world, and China, Japan and India are laughing at America's stupidity." In 2012, Trump tweeted, "The concept of global warming was created by and for the Chinese in order to make U.S. manufacturing non-competitive."

Republican Jim Bridenstine, the first elected politician to serve as NASA administrator, had previously said that global temperatures were not rising. But a month after the Senate confirmed his NASA position in April 2018, he acknowledged that human emissions of greenhouse gases are raising global temperatures.

During a May 2018 meeting of the United States House Committee on Science, Space, and Technology, Representative Mo Brooks claimed that sea level rise is caused not by melting glaciers but rather by coastal erosion and silt that flows from rivers into the ocean.

In 2019, Ernesto Araújo, the minister of foreign affairs appointed by Brazil's newly elected president Jair Bolsonaro, called global warming a plot by "cultural Marxists" and eliminated the ministry's climate change division.

An April 15, 2023, tweet by Republican U.S. Representative Marjorie Taylor Greene said climate change was a "scam", that "fossil fuels are natural and amazing", and that "there are some very powerful people that are getting rich beyond their wildest dreams convincing many that carbon is the enemy". Her tweet included a chart that omitted carbon dioxide and methane—the two most dominant greenhouse gas emissions.

A 2024 analysis found 100 U.S. representatives and 23 U.S. senators—23% of the 535 members of Congress—to be climate change deniers, all the deniers being Republicans.

American and New Zealand climate scientist Kevin Trenberth has published widely on climate change science and fought back against climate change misinformation for decades. He describes in his memoirs his "close encounters with deniers and skeptics"—with fellow meteorologists or climate change scientists. These included Richard Lindzen ("he is quite beguiling but is criticized as "intellectually dishonest" by his peers"; Lindzen was a professor of meteorology at MIT and has been called a contrarian in relation to climate change and other issues.), Roy Spencer (who has "repeatedly made errors that always resulted in lower temperature trends than were really present"), John Christy ("his decisions on climate work and statements appear to be heavily colored by his religion"), Roger Pielke Jr, Christopher Landsea, Pat Michaels ("long associated with the Cato Institute, he changed his bombastic tune gradually over time as climate change became more evident").

Sherwood B. Idso is a natural scientist and is the president of the Center for the Study of Carbon Dioxide and Global Change, which rejects the scientific consensus on climate change. In 1982 he published his book Carbon Dioxide: Friend or Foe?, which said increases in CO₂ would not warm the planet, but would fertilize crops and were "something to be encouraged and not suppressed".

William M. Gray was a climate scientist (emeritus professor of atmospheric science at Colorado State University) who supported climate change denial: he agreed that global warming was taking place, but argued that humans were responsible for only a tiny portion of it and it was largely part of the Earth's natural cycle.

In 1998, Frederick Seitz, an American physicist and former National Academy of Sciences president, wrote the Oregon Petition, a controversial document in opposition to the Kyoto Protocol. The petition and accompanying "Research Review of Global Warming Evidence" claimed that "We are living in an increasingly lush environment of plants and animals as a result of the carbon dioxide increase. [...] This is a wonderful and unexpected gift from the Industrial Revolution". In their book Merchants of Doubt, the authors write that Seitz and a group of other scientists fought the scientific evidence and spread confusion on many of the most important issues of our time, like the harmfulness of tobacco smoke, acid rains, CFCs, pesticides, and global warming.

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Efforts to lobby against environmental regulation have included campaigns to manufacture doubt about the science behind climate change and to obscure the scientific consensus and data. These have undermined public confidence in climate science.

As of 2015, the climate change denial industry is most powerful in the U.S. Efforts by climate change denial groups played a significant role in the United States' rejection of the Kyoto Protocol in 1997.

Research conducted at an Exxon archival collection at the University of Texas and interviews with former Exxon employees indicate that the company's scientific opinion and its public posture toward climate change were contradictory. A systematic review of Exxon's climate modeling projections concluded that in private and academic circles since the late 1970s and early 1980s, ExxonMobil predicted global warming correctly and skillfully, correctly dismissed the possibility of a coming ice age in favor of a "carbon dioxide induced super-interglacial", and reasonably estimated how much CO₂ would lead to dangerous warming.

Between 1989 and 2002, the Global Climate Coalition, a group of mainly U.S. businesses, used aggressive lobbying and public relations tactics to oppose action to reduce greenhouse gas emissions and fight the Kyoto Protocol. Large corporations and trade groups from the oil, coal and auto industries financed the coalition. The New York Times reported, "even as the coalition worked to sway opinion [toward skepticism], its own scientific and technical experts were advising that the science backing the role of greenhouse gases in global warming could not be refuted". In 2000, the Ford Motor Company was the first company to leave the coalition as a result of pressure from environmentalists. Daimler-Chrysler, Texaco, the Southern Company and General Motors subsequently left the GCC. It closed in 2002.

From January 2009 through June 2010, the oil, coal and utility industries spent $500 million in lobby expenditures in opposition to legislation to address climate change.

A study in 2022 traced the history of an influential group of economic consultants hired by the petroleum industry from the 1990s to the 2010s to estimate the costs of various proposed climate policies. The economists used models that inflated predicted costs while ignoring policy benefits, and their results were often portrayed to the public as independent rather than industry-sponsored. Their work played a key role in undermining numerous major climate policy initiatives in the US over a span of decades. This study illustrates how the fossil fuel industry has funded biased economic analyses to oppose climate policy.

This section is an excerpt from ExxonMobil climate change denial.[edit]

From the 1980s to mid 2000s, ExxonMobil was a leader in climate change denial, opposing regulations to curtail global warming. For example, ExxonMobil was a significant influence in preventing ratification of the Kyoto Protocol by the United States. ExxonMobil funded organizations critical of the Kyoto Protocol and seeking to undermine public opinion about the scientific consensus that global warming is caused by the burning of fossil fuels. Of the major oil corporations, ExxonMobil has been the most active in the debate surrounding climate change. According to a 2007 analysis by the Union of Concerned Scientists, the company used many of the same strategies, tactics, organizations, and personnel the tobacco industry used in its denials of the link between lung cancer and smoking.

ExxonMobil has funded, among other groups, 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 granted $16 million to advocacy organizations which disputed the impact of global warming. From 1989 till April 2010, ExxonMobil and its predecessor Mobil purchased regular Thursday advertorials in The New York Times, The Washington Post, and The Wall Street Journal that said that the science of climate change was unsettled.

An analysis conducted by The Carbon Brief in 2011 found that 9 out of 10 of the most prolific authors who cast doubt on climate change or speak against it had ties to ExxonMobil. Greenpeace have said that Koch industries invested more than US$50 million in the past 50 years on spreading doubts about climate change.

Climate change deniers attacked the work of climate scientist Michael E. Mann for years. On 8 February 2024, Mann won a $1 million judgment for punitive damages in a defamation lawsuit filed in 2012 against bloggers who attacked his hockey stick graph of the Northern Hemisphere temperature rise. One of the bloggers had called Mann's work "fraudulent", contrary to numerous investigations that had already cleared Mann of any misconduct and supported the validity of his research.

After Elon Musk's 2022 takeover of Twitter (now X), key figures at the company who ensured trusted content was prioritized were removed, and climate scientists received a large increase in hostile, threatening, harassing, and personally abusive tweets from deniers.

In 2023, increases in climate change denial were reported, particularly on the far right. Climate change deniers threatened meteorologists, accusing them of causing a drought, falsifying thermometer readings, and cherry-picking warmer weather stations to misrepresent global warming. Also in 2023, CNN reported that meteorologists and climate communicators worldwide were receiving increased harassment and false accusations that they were lying about or controlling the weather, inflating temperature records to make climate change seem worse, and changing color palettes of weather maps to make them look more dramatic. The German television news service Tagesschau called this a global phenomenon.

Journalists reported in 2015 that oil companies had known since the 1970s that burning oil and gas could cause climate change but nonetheless funded deniers for years.

Several large fossil fuel corporations provide significant funding for attempts to mislead the public about climate science's trustworthiness. ExxonMobil and the Koch family foundations have been identified as especially influential funders of climate change contrarianism. The bankruptcy of the coal company Cloud Peak Energy revealed it funded the Institute for Energy Research, a climate denial think tank, as well as several other policy influencers.

After the IPCC released its Fourth Assessment Report in 2007, the American Enterprise Institute (AEI) offered British, American, and other scientists $10,000 plus travel expenses to publish articles critical of the assessment. The institute had received more than $1.6 million from Exxon, and its vice-chairman of trustees was former Exxon head Lee Raymond. Raymond sent letters that alleged the IPCC report was not "supported by the analytical work". More than 20 AEI employees worked as consultants to the George W. Bush administration.

The authors of the 2010 book Merchants of Doubt provide documentation for the assertion that professional deniers have tried to sow seeds of doubt in public opinion in order to halt any meaningful social or political action to reduce the impact of human carbon emissions. That only half of the American population believes global warming is caused by human activity could be seen as a victory for these deniers. One of the authors' main arguments is that most prominent scientists who have opposed the near-universal consensus are funded by industries, such as automotive and oil, that stand to lose money by government actions to regulate greenhouse gases.

The Global Climate Coalition was an industry coalition that funded several scientists who expressed skepticism about global warming. In 2000, several members left the coalition when they became the target of a national divestiture campaign run by John Passacantando and Phil Radford at Ozone Action. When Ford Motor Company left the coalition, it was regarded as "the latest sign of divisions within heavy industry over how to respond to global warming". After that, between December 1999 and early March 2000, the GCC was deserted by Daimler-Chrysler, Texaco, energy firm the Southern Company and General Motors. The Global Climate Coalition closed in 2002.

In early 2015, several media reports emerged saying that Willie Soon, a popular scientist among climate change deniers, had failed to disclose conflicts of interest in at least 11 scientific papers published since 2008. They reported that he received a total of $1.25 million from ExxonMobil, Southern Company, the American Petroleum Institute, and a foundation run by the Koch brothers. Documents obtained by Greenpeace under the Freedom of Information Act show that the Charles G. Koch Foundation gave Soon two grants totaling $175,000 in 2005/6 and again in 2010. Grants to Soon between 2001 and 2007 from the American Petroleum Institute totaled $274,000, and between 2005 and 2010 from ExxonMobil totaled $335,000. The Mobil Foundation, the Texaco Foundation, and the Electric Power Research Institute also funded Soon. Acknowledging that he received this money, Soon said that he had "never been motivated by financial reward in any of my scientific research". In 2015, Greenpeace disclosed papers documenting that Soon failed to disclose to academic journals funding including more than $1.2 million from fossil fuel industry-related interests, including ExxonMobil, the American Petroleum Institute, the Charles G. Koch Charitable Foundation, and the Southern Company.

Science editor-in-chief Donald Kennedy has said that deniers such as Michaels are lobbyists more than researchers, and "I don't think it's unethical any more than most lobbying is unethical". He said donations to deniers amount to "trying to get a political message across".

Robert Brulle analyzed the funding of 91 organizations opposed to restrictions on carbon emissions, which he called the "climate change counter-movement". Between 2003 and 2013, the donor-advised funds Donors Trust and Donors Capital Fund, combined, were the largest funders, accounting for about a quarter of the funds, and the American Enterprise Institute was the largest recipient, with 16% of the total funds. The study also found that the amount of money donated to these organizations by means of foundations whose funding sources cannot be traced had risen.

Public opinion on climate change is significantly affected by media coverage of climate change and the effects of climate change denial campaigns. Campaigns to undermine public confidence in climate science have decreased public belief in climate change, which in turn has affected legislative efforts to curb CO₂ emissions.

Climate change conspiracy theories and denial have resulted in poor action or no action at all to effectively mitigate the damage done by global warming. 40% of Americans believed (ca. 2017) that climate change is a hoax even though 100% of climate scientists (as of 2019) believe it is real.

A study in 2015 stated: "Exposure to conspiracy theories reduced people's intentions to reduce their carbon footprint, relative to people who were given refuting information."

Manufactured uncertainty over climate change, the fundamental strategy of climate change denial, has been very effective, particularly in the U.S. It has contributed to low levels of public concern and to government inaction worldwide. A 2010 Angus Reid poll found that global warming skepticism in the U.S., Canada, and the United Kingdom has been rising. There may be multiple causes of this trend, including a focus on economic rather than environmental issues, and a negative perception of the United Nations and its role in discussing climate change.

According to Tim Wirth, "They patterned what they did after the tobacco industry. ... Both figured, sow enough doubt, call the science uncertain and in dispute. That's had a huge impact on both the public and Congress." American media has propagated this approach, presenting a false balance between climate science and climate skeptics. In 2006 Newsweek reported that most Europeans and Japanese accepted the consensus on scientific climate change, but only one third of Americans thought human activity plays a major role in climate change; 64% believed that scientists disagreed about it "a lot".

Deliberate attempts by the Western Fuels Association "to confuse the public" have succeeded. This has been "exacerbated by media treatment of the climate issue". According to a 2012 Pew poll, 57% of Americans are unaware of, or outright reject, the scientific consensus on climate change. Some organizations promoting climate change denial have asserted that scientists are increasingly rejecting climate change, but this is contradicted by research showing that 97% of published papers endorse the scientific consensus, and that percentage is increasing with time.

On the other hand, global oil companies have begun to acknowledge the existence of climate change and its risks. Still, top oil firms are spending millions lobbying to delay, weaken, or block policies to tackle climate change.

Manufactured climate change denial is also influencing how scientific knowledge is communicated to the public. According to climate scientist Michael E. Mann, "universities and scientific societies and organizations, publishers, etc.—are too often risk averse when it comes to defending and communicating science that is perceived as threatening by powerful interests".