By the 1980s, climate science had become quite advanced. Nearly two centuries of successive scientific research had made it clear that the Earth was warming due to increasing carbon dioxide emissions caused by human activities. Sensing a growing threat to the coal, oil, and gas industries, they began to spread doubt about the science. From the day the idea of reducing carbon emissions was raised, a counter-campaign—backed by fossil fuel interests—was launched. They claimed that climate science was immature, carbon emissions did not cause warming, the increase in carbon dioxide was actually beneficial for the planet, and that temperature rise was due to natural causes. At annual global climate summits, their representatives attended in large numbers to prevent any strong decisions to curb carbon emissions.

Their activity involved hiring public relations firms, funding scientists to produce skeptical research, and engaging politicians to oppose climate-related regulations. As a result, despite the growing scientific consensus, public understanding of the issue was confused and delayed for decades — and that was precisely the aim of the corporations.

Climate denial campaigns spent hundreds of millions of dollars on think tanks, media outlets, and research organizations that spread misinformation and attacked genuine scientists. Institutions such as the Heartland Institute, the Cato Institute, and the Competitive Enterprise Institute were at the center of this war. With the goal of undermining the credibility of climate science, they published articles, organized conferences, released reports, and trained the media.

Skeptics and deniers claimed that climate models had errors. But due to the complexity of natural laws, no model can ever be flawless. Still, most climate scientists agree that the sophisticated models developed since the 1980s are excellent representations of climatic patterns.

Moreover, scientists don’t rely solely on models to understand how climate is changing or will change. Theoretical understanding has grown about natural influences on climate, such as changes in Earth’s orbit and axial tilt, and these studies have also supported the conclusion that rising greenhouse gases are responsible for global warming. Analysis of tree rings, ice cores, rock layers, fossilized pollen, etc., helps us understand historical climate and its changes. These natural records, when compared with model projections of human-caused climate changes, show strong alignment.

Instead of blaming greenhouse gases, skeptics point to variations in solar radiation reaching Earth. But for about thirty years, satellites have been measuring how much solar energy reaches the atmosphere. The difference is minimal. Most climate scientists agree that such small variation cannot account for the scale of climate change we’re seeing. Furthermore, if the sun were to blame, both the troposphere (up to about 13 km above Earth) and the stratosphere (from about 13 to 50 km altitude) should warm together. But that’s not happening.

The idea that increased solar brightness is causing warming was dismissed long ago. If that were true, both Earth’s surface and the stratosphere would be warming. Since 1979, satellite data has provided a high-quality record of solar radiation reaching Earth. Some variation is seen during Earth’s orbit, mainly due to the 11-year solar sunspot cycle. But when averaged across cycles, no significant change in solar intensity has been observed. On the other hand, strong evidence supports warming due to greenhouse gases. When warming is driven by greenhouse gases, the surface and lower troposphere warm, but the lower stratosphere cools. This is exactly what has been observed. Although volcanic eruptions also contribute to stratospheric cooling, human activities remain the primary cause.

Scientists have calculated how much surface temperature changes with average incoming solar radiation. They have also assessed how human-produced carbon dioxide, methane, black soot, etc., alter the impact of solar radiation. The opposing effects of particles that reflect sunlight or form clouds, and the complex dynamics of ocean heat absorption, all contribute to estimates of surface temperature rise. Many experts believe that unless massive changes are made in human activity, global surface temperature could rise by as much as 4°C above pre-industrial levels by the end of this century. Even if efforts begin immediately, a 2°C rise is nearly inevitable.

The second IPCC report, published in 1995, stated: “The balance of evidence suggests a discernible human influence on global climate.” Since then, the idea that human actions are causing climate change has grown stronger. About 98% of research papers by climate scientists support this conclusion.

From 1999 for fifteen years, global temperatures rose very slowly. Skeptics pointed to this pause as proof that climate science was flawed. But climate models predict that, naturally, there will be periods of slower warming in the climate cycle. Also, the oceans absorb heat slowly. Surface heat gradually spreads downward into the ocean. Scientists still have relatively limited knowledge of how deep-ocean heat transfer works. And from a time-scale perspective, 10–15 years is too short to determine long-term temperature trends.

Some issues remain unresolved. For example, how Earth’s surface reflectivity changes is not yet fully understood. It’s also unclear how and to what extent methane gas is released from permafrost and the ocean floor. These unknowns become targets for skeptics’ attacks.

Harassment, Defamation, and Attacks

Over the course of several decades, a number of organizations were created in the United States with various agendas. Some aimed to promote the interests of cigarette companies, while others opposed government regulation on various issues. Gradually, many of these organizations turned into hubs for climate change denial. They began spreading confusion about climate science. Major American corporations—especially oil and gas companies—financially supported them. As more and more scientific research throughout the 1990s supported global warming and climate change, the harassment, intimidation, and relentless attacks on climate scientists also escalated. In some cases, these efforts successfully silenced scientists.

In 1989, the American Petroleum Institute formed a task force. Its goal was to deny climate science and sow public doubt about the growing consensus. The Institute spent $5.9 million on this effort. Later, a memorandum titled Global Climate Science Communications Action Plan was released. It outlined plans to recruit, train, and pay scientists who would spread doubt in the media and among the public. The memo explicitly stated: “Build a case against precipitous action on climate change based on scientific uncertainty.”

In 1998, Michael Mann, along with Bradley and Hughes, published a paper in the journal Nature that showed, using a graph, that Earth’s surface temperature was rising dramatically. That graph—resembling a hockey stick—became iconic in climate debates. For the majority of climate scientists, it was undeniable proof of global warming. The ‘hockey stick’ graph illustrated Earth’s temperature changes over a thousand years. For most of that period, temperatures showed only slight fluctuations—represented by the long, flat handle of a hockey stick. But from the second half of the 19th century, the curve began to rise steeply—like the blade of the stick. The IPCC included this graph in its Third Assessment Report in 2001.

In 2006, Al Gore’s documentary An Inconvenient Truth also featured the graph. According to Mann, from then on, he has faced constant harassment and attacks. His emails have been hacked, newspapers and billboards have defamed him, and his family has received threats. His research has been investigated eight separate times by bodies such as the U.S. National Science Foundation and the British House of Commons. None of the investigations found any evidence of data fraud or misconduct. Each time, the investigators concluded that Mann’s methods were sound and his findings could be reliably reproduced. Yet, every time one investigation ended, another would begin.

In 2010, Virginia Attorney General Ken Cuccinelli demanded that the University of Virginia hand over all documents related to its former professor Michael Mann’s research. Cuccinelli claimed it was necessary to determine whether Mann had committed fraud involving taxpayer-funded research during his eleven years at the university. The university refused and fought the matter in court. In 2012, the court ruled against Cuccinelli.

Michael Mann, a paleoclimatologist, was the director of the Earth System Center at Penn State University. One day in 2012, he entered his office with a stack of letters. As he was opening envelopes, his finger touched a white powder inside one. Instinctively, he pushed his chair back and dropped the letter to the floor—some smoke even rose from it. Such events were not unusual in Mann’s life. And Mann is far from alone—many climate scientists in the U.S. and Australia regularly face threats, defamation, and intimidation.

Two government scientists, Jeffrey Gleason and Charles Monnett, researching Alaska, wrote a report stating that they had seen a dead polar bear floating in the Arctic Ocean. They believed it had drowned. The incident was mentioned in An Inconvenient Truth to illustrate the impact of melting Arctic ice. In 2010, the U.S. Office of the Inspector General launched an investigation, claiming it was an ‘integrity issue.’ The investigation dragged on for two years without charges. Even though there was no indication of misconduct, the prolonged inquiry made the scientists’ lives miserable. Monnett announced he would no longer publish scientific papers. Gleason resigned from his job in Alaska. Though very few scientists have quit out of fear of harassment—Monnett and Gleason’s case is an exception—many have stopped speaking publicly about their research. However, the risk of harassment and humiliation has not decreased.

Climate denialists have a wide range of attack methods. A U.S. woman climate scientist once received an email referencing her daughter and invoking the guillotine. The threat worked. A climate modeler at Lawrence Livermore National Laboratory once heard a knock late at night. Upon opening the door, he found a dead, large rat on his doorstep. He then saw a yellow car driving away. In January 2012, a hurricane researcher at MIT discovered dozens of threatening emails in his inbox—using vile language against him and his wife. In 2011, after several climate scientists in Australia were threatened with physical assault and their children with sexual violence, the government intervened and relocated them to safe housing.

Harassment is often accompanied by legal and political attacks. To disrupt scientists’ research, various organizations frequently file lawsuits and use the Freedom of Information Act to request confidential research materials. In 2005, before Michael Mann and other climate scientists were summoned to testify before Congress, Texas Congressman Joe Barton ordered them to provide detailed information on their computer programs, research methodologies, and the sources of their funding. Though all of this is usually disclosed in scientific papers, such demands served no purpose other than harassment.

Paid Promoters

Several climate scientists affiliated with institutions and universities were sued by the American Tradition Institute (ATI). Among them were Michael Mann and NASA scientist James Hansen. ATI demanded access to their correspondence and research documents.

A number of U.S. Senators and Congress members also launched attacks against the concept of climate change. One of the most prominent figures in this campaign was Republican Senator James Inhofe of Oklahoma. Between 2000 and 2008, he received $662,000 in donations from oil companies for his efforts. Similarly, over a span of 27 years, Congressman Joe Barton received a total of $1 million for the same cause. In 2010, Inhofe published a report listing 17 prominent climate scientists, alleging that they were involved in ‘potentially criminal behavior.’ He claimed they had violated three laws and four regulations, including the Federal False Statements Act, which carries a penalty of up to five years in prison.

Timothy Ball, a former professor at the University of Winnipeg, delivered over 600 lectures on science and the environment during the first decade of the 21st century—that’s roughly one every six days. Between 2002 and 2007, he wrote 39 op-eds and 32 letters to the editor in 24 Canadian daily newspapers—averaging at least one piece per month. He also regularly contributed to the skeptics’ website Tech Central Station. Ball appeared in two climate denial documentaries: The Great Global Warming Swindle and Fox News’ Exposed: The Climate of Fear. He was associated with ‘Friends of Science,’ an organization funded by oil and gas companies. Later, he left that group and founded the “Natural Resources Stewardship Project.”

In a 2006 op-ed published in the Calgary Herald, Ball claimed he was Canada’s first PhD in climate science and had taught at the University of Winnipeg for 28 years. He attacked Don Johnson, a professor of environmental science at the University of Lethbridge, in an article. Johnson responded with a letter to the Calgary Herald, stating that Ball had made multiple false claims and had no evidence of serious research in climate or atmospheric science. Ball then sued Johnson. However, in court, Ball admitted to exaggerating—he had taught for only eight years, not 28, and his PhD was in geography, not climate science. The newspaper, siding with Johnson, stated: “The plaintiff (Ball) is viewed as a paid promoter of the agenda of the oil and gas industry rather than as a practicing scientist.” Disgraced, Ball withdrew his lawsuit in June 2007.

Four years later, in 2011, he published another article on the conservative website Canada Free Press, this time attacking climate scientist Professor Andrew Weaver of the University of Victoria. Weaver filed a defamation lawsuit. Canada Free Press issued an apology, removed Ball’s article from their website, and also deleted 200 of his previously published articles.

One of the most well-known critics of climate scientists among skeptics is Steven Milloy, a commentator on Fox News. Previously, he was a paid promoter for the tobacco industry. He now runs the blog junkscience.com, a platform for attacking the idea of global warming and climate change. When funding from the tobacco lobby dwindled in the 1990s, Milloy joined the climate skeptic camp. He received money from Charles and David Koch’s organizations and promoted their agenda in return. Milloy and others like him do not care for rational counterarguments. They continuously launch bizarre theories and lies like missiles from multiple directions.

Around fifteen years ago, the Koch Foundation approved a grant of $150,000 for research by Richard Muller, a physicist at the University of California. Muller was once a favorite among skeptics. Their claim was that global temperature rise was not real, but rather a result of flawed analysis, unreliable weather stations, and the urban heat island effect. Muller and his colleagues spent two years collecting 1.6 billion temperature measurements from 39,000 stations worldwide and examined other data as well. In October 2011, they reported that since 1950, Earth’s temperature had risen by 0.88°C, and this matched other scientific findings. Muller later stated: global warming is a real phenomenon, and it can be said with confidence that the reports on temperature rise so far have not been biased. Since then, some conservatives have shifted their stance. Even those who had previously funded climate skepticism began changing position. Companies like ExxonMobil reduced their financial support.

Organizations on the Payroll

In 1984, the Competitive Enterprise Institute (CEI) was founded in the United States with the goal of opposing government regulation in various fields. These included air quality, dioxin emissions, drug safety, fuel efficiency standards, alcohol labeling, as well as regulations on high-tech industries, e-commerce, intellectual property, and telecommunications. CEI’s stance was that government regulation is bad in all respects.

CEI opposed any measures to tackle global warming. They heavily funded a program called the Earth Summit Program. Through this initiative, they published numerous articles and interviews opposing the proposed actions discussed at the 1992 Rio Climate Summit. In 1997, CEI announced that they would provide experts to speak against the reality of global warming. In 2006, they aired TV advertisements in fourteen American cities in opposition to Al Gore’s documentary An Inconvenient Truth. CEI received funding from Amoco, Philip Morris, and ExxonMobil. Between 1998 and 2005, ExxonMobil alone donated $2 million to them.

In 1989, with support from oil and gas companies as well as other major corporations, the Global Climate Coalition (GCC) was established. Members included ExxonMobil, Amoco, Chevron, the American Petroleum Institute, Shell, Texaco, the U.S. Chamber of Commerce, Chrysler Corporation, General Motors, and the American Forest and Paper Association. A few years after its formation, the GCC hired a PR firm to promote its position on climate change. In 1997, this firm produced and widely circulated a video opposing the Kyoto Protocol. However, some member companies began leaving the coalition when they realized the risk of legal consequences—similar to what Big Tobacco faced for denying the harms of smoking, eventually losing lawsuits and paying $251 billion in compensation. As companies started to pull out one by one, the GCC finally disbanded in 2001.

Cracks had already started to appear within. The GCC had formed a research wing called the Science and Technology Assessment Committee, made up of scientists and technologists from industry. Led by Mobil Oil chemical engineer L.C. Bernstein, the committee produced a report in 1995, which was circulated among GCC members. It stated: “The scientific basis for the potential impact of greenhouse gases like carbon dioxide on the climate is so well-established that it cannot be denied.” Regarding solar variability, the report said that “the minimal differences in solar brightness are too small to cause significant temperature changes on Earth.” The report concluded: “Though there are dissenting theories questioning our overall understanding of climate processes, no viable counter-model exists that challenges the conventional greenhouse gas-induced climate change model with credible scientific reasoning.”

In other words, while oil companies and their paid spokespeople were publicly claiming that fossil fuels don’t cause global warming, their own scientists were saying the opposite. Twelve years later, in 2007, the Bernstein Report was revealed during a court case in California.

The Heartland Institute was originally created to serve the interests of the tobacco lobby. From 1996 to 2006, it received $676,500 in funding from ExxonMobil. Around 15 years ago, the Institute published The Skeptics Handbook, with funding from an anonymous donor. The name of the author, Joanne Nova, was also a pseudonym. The book was printed in 15 languages and 150,000 copies were distributed: 850 journalists, 26,000 schools, 19,000 leaders and politicians, 25,000 copies to Black churches, and 20,000 to college and university trustees received it. Additionally, 60,000 copies were downloaded for free. Heartland’s goal was to cultivate an opinion—especially in schools and colleges—that climate change is a controversial and uncertain issue.

In February 2012, it was revealed that Microsoft, the General Motors Foundation, and others were among the corporate funders of Heartland. The institute also paid certain scientists regularly in exchange for promoting climate denial. For instance, Craig Idso, the head of a climate change denial group in Arizona, received an annual salary of $139,000.

The Cato Institute is a free-market, libertarian organization whose Center for the Study of Science is led by Patrick Michaels, a well-known climate change skeptic. For many years, he has been associated with several fossil fuel-funded organizations and has denied the realities of climate change, the ozone hole, acid rain, and the harmful effects of tobacco.

In 2000, during the U.S. National Climate Assessment, the Cato Institute claimed that climate change would mostly have positive effects in northern regions and that storms and extreme weather events were decreasing. But in the following decade, Arctic sea ice melted at record levels, while in the hot season of 2012, extreme weather events in the United States had doubled. Even after the release of the 2009 National Climate Assessment report, the Cato Institute, the Heartland Institute, and the Competitive Enterprise Institute jointly attacked the report.

The Cato Institute published a climate report deliberately designed to mimic the official, peer-reviewed 2009 report of the U.S. Global Change Research Program (USGCRP) in order to mislead readers and make it appear scientifically credible. They copied the layout and cover design of the original report. However, the Cato report was not based on any peer review, transparency, or expert consensus.

The USGCRP report was prepared with the participation of 13 U.S. government agencies and international scientists, and it presented the current and future threats of climate change in the United States. Cato’s report had no connection to it. While it did acknowledge that human activities are partly responsible for climate change, it downplayed the risks and damages. This was a repeat of the misleading tactics used by climate change denial groups, intended to obstruct government action on climate issues.

Similarly, the Heartland Institute titled its own report the “Nongovernmental International Panel on Climate Change,” deliberately imitating the United Nations’ “Intergovernmental Panel on Climate Change” (IPCC). They even modeled the cover design and layout on IPCC reports to confuse readers.

In 1984, during President Reagan’s Strategic Defense Initiative (SDI) or “Star Wars” program, the George C. Marshall Institute was established in Washington D.C. (It was founded in 1984 and shut down in 2015.) Aside from defense research, the institute also ran campaigns against global warming. Their scientists claimed various things over time, such as: the 20th century wasn’t unusually warm; global warming stopped in 2005; and higher levels of atmospheric CO₂ would accelerate plant growth and make the planet more productive.

In the 1830s, German scientist Justus von Liebig introduced Liebig’s Law of the Minimum, which states that a plant’s growth is not determined by the total resources available but by the scarcest one. For instance, in a desert where water is limited, it’s the lack of water—not CO₂—that limits plant growth. In 2000, a paper by Stan Smith from the University of Nevada was published in Nature, showing that increasing CO₂ results in only minimal growth.

A 2002 study from Stanford University, published in Science, showed that while CO₂ increase may lead to faster plant growth, it is not the sole factor. This phenomenon, called the Carbon Fertilization Effect, can boost photosynthesis but is moderated by other key factors like temperature, water availability, and soil nutrients. Another study published on ScienceDirect.com also noted that while CO₂ may help, temperature often has a more significant impact on mature trees. When factors like warming, nitrogen levels, and rainfall changes are considered, the actual growth increase is marginal.

In 2003, the journal Climate Research published a controversial paper by two Marshall Institute scientists, Sallie Baliunas and Willie Soon, claiming that the 20th century experienced no unusual warming. Following the publication, three editors resigned in protest, and it was later revealed that the study was funded by the petroleum industry.

Between 1998 and 2005, the Marshall Institute received $630,000 from ExxonMobil, as well as funding from at least two other fossil fuel companies. These connections disillusioned their Executive Director, Matthew Crawford, who resigned just five months into the job. According to Crawford, “fellowships were given under the guise of science but actually served other vested interests, and appointments were made based not on merit but on agenda.” One of his tasks had been to develop arguments against global warming.

In 2010, William Happer, a physicist at Princeton University and a former chairman of the Marshall Institute, testified before a House committee saying that increased CO₂ levels were beneficial to plant growth. He claimed that CO₂ is artificially raised in greenhouses to boost productivity. The Marshall Institute shut down in 2015.

Conference of the Skeptics

8:50 a.m. — Scientists had gathered in Copenhagen to present their latest research on global warming. Near New York’s Times Square, a discussion meeting was underway in a conference hall (the event was described in detail in a 2010 report in Britain’s The Guardian). The discussion topic was “Climate Change and Extreme Events: Lies, Damned Lies, and Statistics.” Around 100 people were present. One speaker was wrapping up his talk. He asked the audience how many had understood his statistics-based presentation. About half a dozen hands went up. In the last row, an MIT professor sat with his head tilted back, mouth wide open, sleeping.

This was a conference for those opposing government initiatives to reduce carbon emissions — a gathering of some of the world’s leading contrarian scientists and activists. Their stance: climate change is a relic of the past. Their question: was global warming ever truly a real problem? This marked the beginning of a new campaign — against Obama’s green economy initiatives and aimed at ensuring that the United States did not sign any climate change agreements. In the words of Republican Senator James Inhofe’s protégé, Marc Morano — who dismisses global warming outright as a hoax — this was “an attack on what was happening in the mainstream media, in Congress leadership, and in the White House.”

Participants from the United States, Europe, and elsewhere admitted unanimously that leading scientific institutions and governments ignored their views. But they had not given up. They believed the global financial crisis had given them a chance to score a potential victory in the battle over global warming. The conference was organized by the Heartland Institute in Chicago. According to the institute’s president, Joseph Bast, the U.S. economic crisis had “taken the wind out of the sails” of efforts to impose cap-and-trade or an energy tax (carbon tax) to reduce emissions. In his view, if Obama could not implement cap-and-trade within two months or get the energy bill passed, then those initiatives would have no future.

Nearly 50 individuals and organizations associated with the conference had received a total of $470 million in donations from ExxonMobil and the Koch family.

Scholarly Freedom at Risk

In February 2013, the prestigious psychology journal Frontiers in Psychology published a research paper by scientist Stephan Lewandowsky and his colleagues. The paper was titled “Recursive Fury: Conspiracist Ideation in the Blogosphere in Response to Research on Conspiracist Ideation.” It argued that people who reject climate science are more likely to believe in conspiracy theories. The authors had reached this conclusion through a detailed survey and analysis of statements made on climate-skeptic blogs.

After Recursive Fury was published, Frontiers received threats of multiple lawsuits. The journal removed the paper from its website (although it remained available on the University of Western Australia’s website). The paper was then re-examined and found to be scientifically and ethically sound, with no errors. Nonetheless, out of fear of legal complications, Frontiers permanently withdrew it from their website on March 31, 2014. This incident became a striking example of how scientific research can be undermined by the threat of lawsuits.

In its statement, Frontiers said: after receiving several complaints, the journal conducted a thorough review of the academic, ethical, and legal aspects of the paper and found no faults in any of those areas. Even so, they claimed the legal situation was not sufficiently clear and chose to retract the published article. The researchers involved expressed regret over the legal obstacles to exercising scholarly freedom.

The decision by Frontiers regarding Recursive Fury sparked intense criticism in the scientific community. Many scientists who had submitted papers to the journal sent strongly worded emails, demanding assurances that their work would not be withdrawn under similar circumstances. Some questioned Frontiers’ commitment and judgment in upholding scholarly freedom. The controversy caused significant upheaval in academic circles.

Greenpeace’s Sting Operation

In 2015, in order to highlight the negative aspects of the Paris Climate Agreement, Greenpeace — posing as representatives of a Middle Eastern oil and gas company and an Indonesian coal company — contacted Princeton University physics professor William Happer via email, requesting him to write a report on the benefits of increasing carbon emissions.

William Happer is a prominent U.S. climate change skeptic. He was an energy adviser to former President George H. W. Bush, chairman of the George C. Marshall Institute in the United States, and an adviser to Britain’s Global Warming Policy Foundation. He was invited to testify before a congressional hearing called by Republican presidential candidate and Senate Science Committee chairman Ted Cruz on “climate fanaticism.” For years, he has argued that increasing carbon emissions will ultimately benefit humanity.

Happer agreed to write the report for a fee, but he requested Greenpeace to make the payment not to him directly, but to the CO₂ Coalition — an organization founded in 2015 to shift debate away from fossil fuel criticism. Earlier, for testimony he gave at a Minnesota hearing on the effects of carbon dioxide, he had donated the $8,000 he received from the PBD Energy company to the CO₂ Coalition. In an email, he stated that his fee was $250 per hour, and for four days’ work, $8,000.

He also admitted that his report would likely not pass review in a peer-reviewed scientific journal. He wrote: “I could submit the paper to a peer-reviewed journal, but publication might take a long time, and reviewers and editors might push for changes so that the message becomes that carbon dioxide is a pollutant and not beneficial to human society — which is not what I want to say, nor is it what your client wants.” As an alternative, he suggested using selected reviewers of their own choosing to approve it, although “purists” might object that the process would not qualify as genuine peer review.

Naomi Oreskes, a science historian at Harvard University and co-author of the book Merchants of Doubt — which examines climate change denial movements — told The Guardian: “Happer has been making this claim for about 20 years, that carbon dioxide is good for agriculture, and it has been proven false. Happer’s profile matches exactly the kind of people we wrote about in Merchants of Doubt.”

Alongside Happer, Greenpeace also contacted retired Pennsylvania State University sociologist Frank Clemente, asking him to prepare a report defending coal in response to a study on the high rate of premature deaths caused by coal pollution in Indonesia. He demanded $15,000 for an 8–10 page research paper and $6,000 for writing an opinion piece for a newspaper.

In both cases, the professors also discussed ways to obscure the fact that they were being paid for the reports. Clemente told The Guardian that he had worked as a consultant for many industries that improved people’s living standards. He said he was proud of his research and believed that clean coal technology was a pathway to reliable and affordable electricity, as well as a way to reduce global energy poverty and improve the environment. PBD Energy frequently cited his research to argue that expanding coal use in developing countries would help alleviate global poverty — a claim even the World Bank has rejected.

The Greenpeace sting operation revealed that it is possible to get professors from prestigious universities to write reports sowing doubt about climate change while concealing fossil fuel company sponsorship. Such reports, funded by various fossil fuel companies, are used to plant doubt in the public mind, influence public opinion on climate change, and block the possibility of strong measures to combat global warming.

Climate change deniers have repeatedly shifted their stance — at times claiming, “Climate change isn’t happening,” then saying, “It’s happening, but not because of human activity,” and later, “It’s happening, but there’s no need to worry.” Smearing scientists as corrupt, branding activists as anti-progress, calling journalists liars, launching personal attacks on experts, and tarnishing reputations by leaking emails — all are key tactics in the climate change denial playbook.

Protecting the Fossil Fuel Industry

Just as the tobacco industry once acted to deny the link between tobacco products and cancer in order to protect its business, climate change skeptics have been doing the same to protect the fossil fuel industry. Looking at the organizations created to deny climate change, it becomes clear that their main function is to financially support industry-friendly experts, conceal information from the public to secure corporate profits, and deny the industry’s role in harming public health.

In 2009, ahead of the Copenhagen Climate Change Conference, hackers broke into the emails of climate researchers at the University of East Anglia. Out of thousands of emails, skeptics selectively picked a few that were taken out of context. The aim was to convince the public that the researchers had manipulated data to mislead them about the reality of climate change. The incident became known as the “Climategate” scandal.

The matter was covered in the U.S. media for months, particularly in conservative outlets. Later, multiple independent investigations found no wrongdoing in the scientists’ research. However, the results of these investigations were barely publicized, leading to a decline in public trust in climate science.

A few years ago, a scientist leaked several documents revealing the names of financial backers of the Heartland Institute, a leading organization attacking climate science. After activists increased pressure, corporations such as State Farm Insurance and General Motors cut ties with the influential Heartland Institute. Several other corporations decided they would no longer publicly align themselves with climate change denial.

Presidential Elections and the Fossil Fuel Lobby

After winning the 2008 U.S. presidential election, Democratic candidate Barack Obama declared that, in the coming days, the country that led the race for renewable energy would also lead the global economy.

Under Obama administration American Recovery and Reinvestment Act (2009) included over $90 billion for clean energy: Wind and solar power, energy efficiency in buildings, electric vehicles and battery technology. This step helped jumpstart the U.S. clean energy industry. Obama introduced regulations to limit methane emissions from oil and gas production. His administration made rules for major emitters to report greenhouse gas emissions. On the other hand under the Clean Air Act Environmental Protection Agency (EPA) was authorised to classify CO₂ as a pollutant.

Obama set tough corporate average fuel economy (CAFE) standards for cars and trucks. Automakers were required to nearly double fuel efficiency by 2025 (to about 54.5 mpg). These steps helped reduce oil consumption and emissions significantly. On the other hand EPA took initiative to limit carbon emissions from power plants, especially coal-fired ones. This was aimed to cut power sector emissions by 32% by 2030 from 2005 levels. Facing legal challenges this was never fully implemented, but it showed administration’s intention. Obama’s promotion of renewable energy, reforms and expansion of the power grid, and measures to reduce emissions made him a thorn in the side of the fossil fuel industry and climate skeptics.

Generally, Republican politicians are skeptical about climate change and have closer ties with the oil, gas, and coal industries. As a result, during the 2012 U.S. presidential election, the energy sector came out strongly in support of Republican candidate Mitt Romney. In the 2016, 2020, and 2024 elections as well, the Production Tax Credit (PTC) for wind and solar energy remained a political issue. Republicans opposed giving PTC benefits for clean or alternative energy production, arguing that when the PTC expired in 2012, it should not be renewed. Romney shared the same view.

The oil, gas, and coal industry leaders were determined to defeat Barack Obama. They wanted fossil fuel consumption to rise. Questioning Obama’s clean energy program, they ran television ads, criticized his strong measures against air pollution, and attacked delays in approving the Keystone Pipeline from Canada. In ads funded by oil companies through the “American Energy Alliance,” they claimed that since Obama became president, gas prices had nearly doubled, and urged voters to “Tell Obama that ineffective energy policies must end.” Two months before the election, $153 million was spent on television ads promoting greater use of coal, oil, and gas drilling, while attacking alternative energy. In contrast, ads supporting clean energy, and Obama’s policies against global warming and air pollution, cost just $41 million in the same period. Energy was the third-most discussed topic after jobs and the economy. In the previous 2008 election, green energy ads outspent fossil fuel ads — $152 million versus $101 million.

In the earlier election, the Alliance for Climate Protection, supported by Al Gore, had spent $32 million, emphasizing the need for legislation to combat global warming. That organization later changed its name to the Climate Reality Project. In the 2012 election, they did not spend anything on ads, knowing that their resources would be drowned out by the flood of fossil fuel money.

Romney promised to allow massive drilling on federal coastal lands, end the PTC for wind and solar power, and roll back restrictions that discouraged coal-fired power generation. Thus, the fossil fuel industry generously funded his campaign. The American Petroleum Institute, backed by gas companies, spent the most. Their main campaign slogan was, “I am an Energy Voter.” They criticized both Obama’s move to reduce drilling and his proposal to end oil industry subsidies. Up until two and a half months before the vote, they had spent about $37 million on TV ads to that effect.

The American Energy Alliance claimed that President Obama was essentially shutting down energy production on U.S. land and coasts. To defeat him, they spent $7 million on TV and other ads. Dozens of companies and organizations campaigned for more fossil fuel production and against the Obama administration. Romney received at least $130 million in campaign contributions from them, while Obama received only $950,000, and a mere $78,000 from the green energy sector. This resulted in a huge financial disparity in campaign resources.

In August 2012, Romney organized a fundraising dinner charging $50,000 per plate. At that time, oil and gas executives urged him to loosen legal restrictions on the fossil fuel industry and permit more drilling on federal lands.

Despite all this, Romney lost. Analysts have cited many reasons, but one major factor was that 70% of Americans believed the government should support the alternative energy industry. Wind and solar power had already become part of the mainstream in the U.S. Under Obama, initiatives for a smart grid, improved energy efficiency, and demand-side energy management had begun. Obama’s US worked with China (then the world’s largest emitter) on a bilateral climate agreement in 2014. This U.S.-China pact helped pave the way for the Paris Agreement. Obama played a key role in negotiating and signing the Paris Agreement (2015), the first global accord where nearly every country committed to reducing emissions. The U.S. pledged to cut emissions by 26–28% below 2005 levels by 2025.

Today, 21.4% of U.S. electricity comes from renewable sources, including hydropower — surpassing the amount generated by more than 100 nuclear reactors back in 2011. However, Republican opposition blocked the development of alternative energy or carbon policies. In Obama’s first term, the Waxman–Markey Bill sought to reduce emissions. While the bill passed the House, it failed in the Senate due to Republican resistance.

When Obama won a second term, his victory was crucial for the fight against climate change. He directed the Environmental Protection Agency (EPA) to set carbon emission standards for new power plants by 2013 and for all power plants by 2014. He announced that all fossil fuel subsidies would be ended, while government funding for alternative energy would increase so that wind and solar production could double by 2020. He also declared that in 2015, at the Paris UN Climate Change Conference, the U.S. would work with other countries to reduce emissions — and that indeed happened.

However, after Obama, Republican Donald Trump came to power. He undermined emission-reduction efforts and withdrew the U.S. from the Paris Agreement. Under Trump, suppression of science reached an extreme. A 2021 study by the Climate Social Science Network documented how right-wing climate denial organizations, emboldened by Trump’s support, coordinated aggressive attacks on climate scientists, research institutions, and university departments. The report said that the Trump administration gave these groups direct access to the White House and Department of Energy policymakers, accelerating anti-science and anti-climate agendas.

A 2020 report by the Union of Concerned Scientists (UCS) described in detail how the Trump administration systematically suppressed, distorted, and undermined scientific research and expert opinion across government agencies. Senior officials ignored scientific data and reports, removed key information from websites, cut research budgets, banned the use of the term “climate change,” and dismantled or stacked scientific advisory committees with industry loyalists. During that period, scientists at the EPA, DOE, and National Oceanic and Atmospheric Administration (NOAA) faced pressure to alter or hide their climate research.

According to a 2020 survey conducted by the UCS and Iowa State University, nearly 50% of federal scientists said they experienced political interference under Trump. Many were told to remove climate-related information from reports; some faced retaliation; others were transferred for resisting political pressure. Despite relentless attacks, the scientific community did not back down. Michael Mann and others continued publishing research, speaking publicly, and defending their work in court. They understood this was not just about climate — it was about truth, justice, and the future of humanity.

As Michael Mann put it, “They wanted to erase scientific reality. But we did not stay silent.” It was a broad, well-planned assault on truth itself, undermining scientific reasoning. Trump was the most visible face of this attack, but its roots were older and deeply entrenched. Science historian Naomi Oreskes and political scientist Erik Conway analyzed this in detail in their 2010 book Merchants of Doubt. They showed how a small group of scientists, once involved in Cold War defense policy, later joined conservative think tanks and fossil fuel companies to spread doubt about various scientific issues — from the harms of smoking to acid rain, the ozone hole, and climate change. Their goal was to delay regulatory action to protect corporate profits.

Public understanding of climate change was deliberately clouded. A 2019 study in Nature Climate Change found that misinformation and disinformation significantly reduced public concern about global warming and support for climate policies in the U.S. The Trump administration even directed the U.S. Geological Survey (USGS) to limit climate modeling to the year 2040 instead of 2100, concealing long-term warming trends.

Later, Democratic President Joe Biden rejoined the Paris Agreement and took steps to reduce emissions and expand renewable energy production. When Trump returned to power, he overturned those positive measures. In the U.S., as in Australia, fossil fuel companies finance a large share of campaign costs for presidents who protect their interests. This way, they obstruct carbon-reduction policies, hinder alternative energy development, and block meaningful climate action.

Recent Research

The trend of climate change denial — or strong skepticism — remains prevalent in the United States. In February 2024, a study jointly published by two scientists in Nature used Twitter (now X) data along with geolocation information, applying artificial intelligence and network analysis to map and profile climate change deniers across the country. The analysis found that 14.8% of Americans do not believe in climate change. This skepticism or denial is highest in the central and southern regions of the United States, driven largely by the popularity of specific political ideologies in those areas. Other contributing factors include educational attainment, COVID-19 vaccination rates, the intensity of carbon emissions in the regional economy, and lower income levels.

The study also revealed how cold weather events and major summits are exploited by social information networks to sow seeds of distrust toward climate change and science. The most influential figure in this network is former U.S. President Donald Trump, followed by conservative media outlets and right-wing activists.

Denial is particularly entrenched in areas where local economies are more dependent on fossil fuels and where rural communities and the general public lack a strong scientific mindset. Social media serves as the primary weapon for spreading misinformation to millions of network users — something that was also evident in reactions to COVID-19 vaccine refusal.

In December 2017, after a snowstorm, a tweet from Trump expressing doubt about global warming inspired climate change skeptics to post tweets claiming that climate change was meaningless. According to them, the concept of climate change is a fraud or conspiracy theory designed to manipulate people into bearing the costs of achieving zero carbon emissions — a scheme that supposedly generates vast wealth for the rich. Conservative media, right-wing activists, and misinformation networks amplified such claims widely on Twitter. Similar tweet storms erupted among skeptics about snowstorms in Texas, the Mid-Atlantic region, and New England. In both cases, skeptics argued that climate change is not real.

Using Twitter data, the researchers applied AI and network analysis to reveal a detailed social map of climate change denial in the U.S. at the state and county levels. They identified geographic clusters of denial in Republican-leaning counties, especially in rural areas with lower college attendance rates. The study found that people who vote for Republican candidates tend to trust Trump’s tweets about climate change more than other climate-related news.

The researchers also found fake experts among the 7.3 million sample tweets — individuals with no knowledge or expertise in climate science but who still spread skeptical messages. They act as trusted messengers because they share the same moral values as their audience. A prime example is Trump’s skeptical tweet about the 2018 IPCC climate report, which his supporters spread widely. To this day, they portray climate change not as the result of human activity, but as a purely natural phenomenon.

References:

1. Ross Gelbspan, Boiling Point: How Politicians, Big Oil and Coal, Journalists, and Activists have Fueled a Climate Crisis—and What We Can Do to Avert Disaster, New York: Basic Books, 2004.
2. Thomas Gale Moore, Climate of Fear: Why We Should Not Worry About Global Warming, Washington DC: Cato Institute, 1998.
3. Naomi Oreskes, Erik M. Conway, Merchants of Doubt Paperback, Bloomsberry, May 2011.
4. “Transcript: Obama’s Speech on Renewable Energy Policy,” The New York Times, 23 October 2009, https://www.nytimes.com/2009/10/24/us/politics/24obama.text.html
5. John W Farley, “Petroleum and Propaganda: The Anatomy of the Global Warming Denial Industry,” Monthly Review Vol. 64, No. 1, May 2012, https://doi.org/10.14452/MR-064-01-2012-05_4
6. Leslie Larson, “Al Gore Likens Global Warming Deniers to Slavery, Apartheid Perpetrators,” Daily News, 12 August 2013, updated 10 January 2019, https://www.nydailynews.com/2013/08/22/al-gore-likens-global-warming-deniers-to-slavery-apartheid-perpetrators/
7. Eric Lipton and Clifford Krauss, “Fossil Fuel Industry Ads Dominate TV Campaign,” New York Times, 13 September 2012, https://www.nytimes.com/2012/09/14/us/politics/fossil-fuel-industry-opens-wallet-to-defeat-obama.html
8. Sonia Whitehead, “The First Rule of Climate Change Research: Don’t Mention Climate Change,” The Guardian, 13 September 2013, https://www.theguardian.com/global-development-professionals-network/2013/sep/13/climate-change-research-language-bbc
9. Michael Mann, “The New IPCC Climate Change Report Makes Deniers Overheat,” The Guardian, 28 September 2013, https://www.theguardian.com/commentisfree/2013/sep/28/ipcc-climate-change-deniers
10. Dan Becker and James Gerstenzang, “Climate Deniers Meet Joe Camel: Column,” USA Today, 10 October 2013, https://www.usatoday.com/story/opinion/2013/10/10/global-warming-science-cancer- olumn/2959009/
11. Dana Nuccitelli, “Fox News Defends Global Warming False Balance by Denying the 97% Consensus,” The Guardian, 23 October 2013, https://www.theguardian.com/environment/climate-consensus-97-per-cent/2013/oct/23/climate-change-climate-change-scepticism
12. Dan Becker and James Gerstenzang, “Climate Deniers; Strategy of Confusion,” Consortium News, 27 October 2013, https://consortiumnews.com/2013/10/27/climate-deniers-strategy-of-confusion/
13. Graham Readfearn, “Australia’s Renewables Adviser Scrapes the Bottom of the Climate Denialist Barrel,” The Guardian, 24 February 2014, https://www.theguardian.com/environment/planet-oz/2014/feb/24/climate-change-dick-warburton-sceptic-australia-renewable-energy-target-review
14. Graham Readfearn, “Lord Lawson Climate Sceptic Think-Tank’s Report Rebuked by Scientists,” The Guardian, 6 March 2014, https://www.theguardian.com/environment/ planet-oz/2014/mar/06/lord-lawson-climate-sceptic-thinktank
15. Elaine McKewon, “The Journal That Gave in to Climate Deniers’ Intimidation,” The Conversation, 1 April 2014, https://theconversation.com/the-journal-that-gave-in-to-climate-deniers-intimidation-25085
16. Dana Nuccitelli, “The 97% v the 3% – Just How Much Global Warming are Humans Causing?” The Guardian, 15 September 2014, https://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/sep/15/97-vs-3-how-much-global-warming-are-humans-causing
17. Suzanne Goldenberg, “Greenpeace Exposes Sceptics Hired to Cast Doubt on Climate Science,” The Guardian, 8 December 2015, https://www.theguardian.com/environment/2015/dec/08/ greenpeace-exposes-sceptics-cast-doubt-climate-science#
18. Tom Clynes, “The Battle Over Climate Science,” Popular Science, 21 May 2021, https://www.popsci.com/science/article/2012-06/battle-over-climate-change/?nopaging=1
19. Jeremiah Bohr, “The Structure and Culture of Climate Change Denial,” Footnotes, Summer 2021, Vol. 49, Issue 3, https://www.asanet.org/footnotes-article/structure-and-culture-climate-change-denial/
20. Dimitrios Gounaridis and Joshua P. Newell “The Social Anatomy of Climate Change Denial in the United States,” Nature, 14 February 2024, https://doi.org/10.1038/s41598-023-50591-6
21. Government Accountibility project, https://whistleblower.org/politicization-of-climate-science/ global-warming-denial-machine/brief-cato-institutes-addendum
22. USGS Scientists Ordered Not to Model Long-Term Climate Impacts, https://climate.law.columbia.edu/content/usgs-scientists-ordered-not-model-long-term-climate-impacts
23. John Byrne, Job Taminiau, Joseph Nyangon, “American Policy Conflict in the Hothouse: Exploring the Politics of Climate Inaction and Polycentric Rebellion”, Energy Research & Social Science, Volume 89, July 2022, 102551, https://www.sciencedirect.com/science/article/pii/ S2214629622000573
24. Jeffrey Mervis, “Employees Protests Against Trump Science Policies Spread to NSF”, Science Adviser, Jul 22, 2025, https://www.science.org/content/article/employees-protests-against-trump-science-policies-spread-nsf22
25. Adam Barnett, “Mapped: The Tory Network of Climate Denial and Fossil Fuel Funding”, Jun 12, 2024, De Smog, https://www.desmog.com/2024/06/12/mapped-tory-network-climate-denial-fossil-fuel-funding/

[Pradip Dutta is a prominent anti-nuclear and environmental activist based in Kolkata and an influential member of citizen movements opposing nuclear projects (such as Haripur). He is also the author of the critical work Nuclear Power: The Reality behind the Hype, which exposes the risks and dubious promises of nuclear energy.]