The FP Guide to Climate Skeptics

Can't tell the legitimate concerns from the nonsense? FP is here to help.

By and , a former associate editor at Foreign Policy.
AFP/Getty Images
AFP/Getty Images
AFP/Getty Images

The field of climate science is under duress, which is wholly different than saying it's discredited. While recent headlines about the woes of U.N.-led efforts to assemble a comprehensive picture of the science have caused gleeful headlines on The Drudge Report and other skeptical media outlets, the vast weight of the evidence -- from melting glaciers to warming oceans to satellite temperature readings, and much more -- still points to a changing climate caused by human activity.

The field of climate science is under duress, which is wholly different than saying it’s discredited. While recent headlines about the woes of U.N.-led efforts to assemble a comprehensive picture of the science have caused gleeful headlines on The Drudge Report and other skeptical media outlets, the vast weight of the evidence — from melting glaciers to warming oceans to satellite temperature readings, and much more — still points to a changing climate caused by human activity.

So why have we heard so much lately about climate-science controversies? One reason is that the stakes are incredibly high: On the one hand, mainstream climate scientists and environmental advocates who believe that there are severe consequences to failing to curb greenhouse-gas emissions; on the other, a loose coalition of skeptical or contrarian scientists, conservatives, industry interests, and outright cranks who may disagree on specific issues, but tend to believe the costs, economic and otherwise, of acting are staggering.

The second reason may be something of a bunker mentality evident at some top climate-research centers. In part because criticisms are so strident, some inside the system have complained that decisions are made by a relatively small circle of mutually supportive insiders. There have been complaints of articles being kept out of scientific journals, or peer comments that haven’t been adequately considered. Most reporters aren’t qualified to make individual scientific assessments, so they have to take some of what scientists, or their detractors, say at face value. But it is clear that the tensions are running high, and a troubling sense of hostility has long since polarized the debate, even as the real-world evidence of climate change has piled up.

Climate skepticism covers a broad range of views. A first group — call them the professionals — has often raised legitimate questions, whether about methodology and transparency, and stuck more or less to a scientific critique about different aspects of climate science. And then there are the shouters, who don’t add much more than sensationalism, confusion, and outright deception to the debate. To sort out the noise from the serious concerns, FP is here to help.


Who is he? Economist at the University of Guelph in Ontario; fellow at the Fraser Institute, a free-market think tank

Chief beef: the statistics and tree-ring data behind the so-called hockey-stick graph

Telling quote: "What the hockey-stick graph did, it created the impression that you can use statistical data from all around the world and derive one big picture — and that was where they went wrong." —interview with FP

Role: McKitrick was among the first to take a swipe at the famed "hockey-stick graph," a reconstruction of temperature in the Northern Hemisphere for the past 1,000 years that has been featured prominently by the Intergovernmental Panel on Climate Change (IPCC), and in Al Gore’s movie An Inconvenient Truth. The task of assembling the graph, so dubbed because of the dramatic shape of the temperature curve, which rose slowly for centuries then shot upward in recent decades, was a monumental challenge. Modern scientists have thermometer readings from the mid-1800s from across Europe and North America, and after World War II, thermometer readings from around the globe. But for years prior to that, scientists can only infer temperatures using what’s called "proxies," such as ice cores or tree rings, whose annual growth can be correlated with annual temperature variations.

The graph resulted from research by climatologists Michael Mann, Raymond Bradley, and Malcolm Hughes that used multiple proxies, including tree rings, coral, ice cores, sediments, and historical records. They found that average temperatures had remained relatively stable for most of the past millennia, but had started to rise steeply around 1900, when the Industrial Revolution kicked into full gear in Europe and North America, with new factories and automobiles pumping new sources of carbon dioxide emissions.

As it attracted more attention from the public and press, their graph also became a target of attack, including from researchers outside the climate community. Beginning in 2003, McKitrick, along with retired Canadian mining executive Stephen McIntyre, began to probe two aspects of the research: the statistical method and the reliability of certain tree-ring samples, which they charged exaggerated the warming effect. McKitrick maintains, "The data and the methods they used meant you couldn’t draw conclusions."

Subsequent research, such as by P. Huybers (pdf) of the Woods Hole Oceanographic Institution, however, found that McKitrick and McIntyre’s work was itself flawed, and other peer-reviewed studies affirmed the basic pattern of the original study. Mann et al. have continued to refine their data, including in an article (pdf) published last November in Science.

The debate has attracted a lot of popular attention, but scientists who work in the climate field tend to regard it as an "ink-blot issue." In other words, it’s possible to come up with a variety of justifiable methodological choices, as well as endless objections to those choices. A related, and equally endless, debate rages over who has authority to speak on climate issues — some scientists, including Mann, think an economist has no role picking bones, while others have been more welcoming of critiques from specialists outside the field.


Who is he? Environmental studies professor at the University of Colorado-Boulder and a fellow of the university’s Cooperative Institute for Research in Environmental Sciences; author of The Honest Broker: Making Sense of Science in Policy and Politics

Chief beef: Hurricanes and the bottom line

Telling quote: "We cannot make a causal link between increase in greenhouse gases and the costs of damage associated with hurricanes, floods, and extreme weather phenomena." —interview with FP

Role: Pielke, whose father is also a scientist and an outspoken critic of the IPCC, is emblematic of just how confusing traditional labels are: For his work questioning certain graphs presented in IPCC reports, Pielke has been accused by some of being a climate change "denier." Meanwhile, for his work on adaptation, he has been accused by others of being an "alarmist."

One of Pielke’s main additions to larger climate debate has been participation in studies and workshops that have concluded, in his words, "We cannot make a causal link between increase in greenhouse gases and the costs of damage associated with hurricanes, floods, and extreme weather phenomena." Whereas An Inconvenient Truth presented worsening storms as reason to support greenhouse gas mitigation, Pielke thinks that increased costs of disasters in recent years are due to "one overriding factor — more wealth, more people, more property in harm’s way." He took issue with the IPCC for one chart in its 2007 report, which seemed to imply causation when there was, if anything, only circumstantial evidence in his eyes. "Mine is an argument against using disasters as a justification for greenhouse gas emissions."

But his refutation of what he saw as sloppy logic certainly does not imply skepticism about climate change and the need to take mitigation and adaptation efforts seriously, he insists. In outlets like The New Republic and Yale Environment 360, Pielke has articulated a more nuanced point of view, often arguing for greater distinctions between debates about scientific integrity and those about public policy. For his part, he thinks, "Climate change is a huge problem, and it’s a problem linked to human activity. Greenhouse gases are an important part of that, but it’s not only greenhouse gases. And we need to respond accordingly."

*Editor’s note: Pielke has informed the editors of FP that he strongly objects to being included on a list titled "Climate Skeptics." The aim of the list was, as the introduction states, to separate "the noise from the serious concerns" with regards to those offering critiques of either climate science or institutions charged with presenting climate science to the public or policy-makers; the article was explicitly not intended to equate the viewpoints of all people contained on the list. Pielke has been quoted in the mainstream media voicing concerns about the IPCC, as in today’s Wall Street Journal, as well as questioning sloppy logic on the part of some environmentalists, for instance objecting to overstatements about hurricanes being linked to global warming. 


Who is he? Climate scientist and director of the Earth System Science Center at the University of Alabama in Huntsville; fellow of the American Meteorological Society

Chief beef: Atmospheric temperature readings

Telling quote: "If you want to measure temperatures, the popular surface data sets are not the ones to use." —interview with FP

Christy, a lead author for sections of the 2001 IPCC report, is a climatologist who has expressed a minority viewpoint, yet retains the fundamental respect of his peers. In such a polarized debate, that is a rarity.

Christy’s concerns center on whether land-surface temperatures or lower-atmospheric temperatures are the most reliable data sources to understand a changing climate. In 1990, he joined with a colleague, Roy Spencer, to use measurements taken by NASA satellites since 1979 to produce the first global atmospheric temperature data. His initial findings showed a lesser degree of warming than most climate models predict, leading him to question those models. However, in 2005, subsequent peer-reviewed studies examining Christy and Spencer’s data found that a missing sign and an arithmetic error meant that their findings, if not the insight of using NASA satellite readings, were flawed. An exchange between Christy and Spencer and also the scientific teams of Carl Mears and Frank Wentz, and Steven Sherwood and John Lanzante, played out in the letters of Science magazine. This back-and-forth is sometimes cited as an example of how self-correcting science should work.

"I respect him," Pielke says. "I disagree with him, but I respect him."


Who is he? Atmospheric physicist and professor of meteorology at the Massachusetts Institute of Technology; member of the National Academy of Sciences; contributing expert to the free-market Cato Institute and the industry-funded George C. Marshall Institute

Chief beef: everything about climate science

Telling quote: "Climate science … may be the first of the physical sciences that has become a part of the political process." —interview with FP

Lindzen is a decorated scientist who doesn’t think that carbon dioxide has a significant effect on the Earth’s temperatures. "If you double carbon dioxide and do nothing else, that only produces 1 degree of warming," he says. He’s a distinct minority in the field, and neither his scientist peers who dispute his findings nor the more polemic climate skeptics who find his research useful know what to make of him. He commands respect from some scientists interviewed, even those who disagree with him, despite having worked as a consultant for the coal industry, while others charge he has effectively made the transition from working scientist to professional shill.

His own political leanings are clear (he sees climate advocates as wanting "to roll back industrial society" and an excuse "to redistribute global wealth"). Perhaps ironically, one of his chief conjectures is about how mixing science and politics is detrimental to both, a concern echoed by those with precisely opposite ideological leanings. As the 70-year-old tells it: "Climate science always been a small backwater field, mostly [composed of scientists who] considered themselves atmospheric or oceanic scientists…. It was not a particularly strong field. In the 1960s and 70s, a number of people in the environmental movement began to look to climate as a vehicle [to advance an agenda]…. It may be the first of the physical sciences that has become a part of the political process."


Who is he? Danish social scientist and professor of business; author of The Skeptical Environmentalist and Cool It

Telling quote: "Climate change is happening, it’s man-made, it’s a problem, but it’s not the end of civilization." —interview with FP

Role: Lomborg thinks the mainstream global-warming movement doth protest too much. So, too, he believes, do most climate skeptics. "It’s unlikely that we will make good policy judgments if we follow either side," he says. "To either deny [climate change] entirely or to say it’s the end of mankind — neither seems to be in accordance with working toward the best solution."

Most climate-change-mitigation advocates have overhyped the science and underdelivered on policy, Lomborg argues. Attempts to reach and enforce binding emissions treaties at U.N. climate summits at Rio de Janeiro, Kyoto, and Copenhagen have disappointed, largely because of the high costs associated with carbon mitigation. And so Lomborg advocates a different approach: "Where do you do most good for each climate-change-fighting dollar you spend — geo-engineering or R&D on green energy technology?… If you can make solar panels cheaper than fossil fuels by 2040, then people will willingly use them."

His contrarian viewpoint has made him a darling of the Wall Street Journal editorial page and other conservative outlets. Yet Lomborg says that his own ideology is "probably left of center, even in Denmark" and wouldn’t necessarily make him feel at home at the Cato Institute. Most of his critics are on the left, including author Howard Friel, whose recent book The Lomborg Deception took him to task for allegedly playing fast and loose with sourcing, logic, and footnotes in his books. (Lomborg told FP that Friel never contacted him for clarification in the course of writing the book and assumed bad intentions at points of ambiguity. Lomborg has responded at length to Friel’s critique here.)

In 2003, Lomborg faced charges of scientific dishonesty that were reviewed by the Danish Committees on Scientific Dishonesty; their ruling found his work was "contrary to the standards of good scientific practice" but not characterized by "[bad] intent or gross negligence." The controversial finding was later overruled, however, by the Danish Ministry of Science, Technology and Innovation.


Who is he? Theoretical physicist and mathematician, formerly of the Institute for Advanced Study

Chief beef: Whether the potential dangers posed by global warming have been exaggerated

Telling quote: "[Climate models] do not begin to describe the real world that we live in. The real world is muddy and messy and full of things that we do not yet understand. It is much easier for a scientist to sit in an air-conditioned building and run computer models, than to put on winter clothes and measure what is really happening outside in the swamps and the clouds. That is why the climate model experts end up believing their own models." —A Many-Colored Glass: Reflections on the Place of Life in the Universe

Role: Thanks to his prominence as a theoretical physicist and popularizer of science, as well as his leftish political affiliations — he has long been active in the anti-nuclear movement — Dyson is seen by many as bringing credibility to climate-change skepticism. The 86-year-old scientist doesn’t dispute that carbon dioxide levels in the atmosphere are increasing because of human activity, but thinks the warming effect may be exaggerated, and in any case is not necessarily harmful. "The fact that the climate is getting warmer doesn’t scare me at all," he has said, believing that most places are better off with a warmer climate and that human technology will advance fast enough to offset the worst effects of pollution. Most famously — or notoriously — he thinks that "carbon-eating trees" could one day be bioengineered to reduce carbon dioxide levels.

Whatever the scientific truth, which Dyson admits he isn’t positive about, he doesn’t think that the case for global warming is sufficient to curtail economic development or take resources away from more pressing problems like reducing poverty. Dyson has openly attacked outspoken NASA scientist James Hansen as well as Al Gore, whom he was quoted calling a "propagandist" and "opportunist" in a widely read New York Times Magazine cover story published in March 2009.

Mainstream scientists mostly dismiss Dyson’s views as the eccentricities of an aging scientist well out of his area of expertise. "There are bigger fish to fry than Freeman Dyson," says Hansen.


Who is he? Former London banker, freelance mathematician, and analyst

Chief beef: missing data, transparency

Telling quote: "The fundamental point, perhaps, is that scientists are human — which implies that scientific research is a human affair. Transparency and accountability are, in general, prerequisites for integrity in human affairs." —interview with FP

Role: When scientists raise issue with the work of other scientists, they typically publish concerns in papers in peer-reviewed journals. Not so with Keenan, a former City of London banker, who instead began with fraud accusations.

When attempting to establish an accurate past global temperature record, one question scientists have raised is to what extent the location of meteorological centers might impact or skew data. Specifically, does the fact that temperature readings are most often taken near large population centers — with "urban heat islands" such as surface parking lots — skew temperatures upward? A team of researchers, including Phil Jones at the Climactic Research Unit at Britain’s University of East Anglia and Wei-Chyung Wang, a climatologist at the State University of New York (SUNY)-Albany, published a paper in Nature in 1990 that examined this question using data that included readings from multiple Chinese meteorological stations and found the urban heat bias to be minimal. The paper has been cited in IPCC assessments, among other places.

Keenan, now a freelance analyst, wanted to know more about where the data came from. In particular, he was concerned that temperature readings Wang obtained lack backup documentation as to how reliable certain temperature stations in China were, how they had been maintained, and whether their locations had varied over time. Keenan also filed an accusation of scientific fraud with SUNY-Albany, where Wang works — raising the temperature of the dispute immensely.

One of Keenan’s contentions, as he wrote in a letter to Wang’s university, was that "when a station moves, the temperature data from before the move is not, in general, directly comparable to the data from after the move." His second, broader concern, as he wrote in an email to FP: "Regarding transparency, the data and methods used by scientists should be publicly available."

Since then, Jones has published another peer-reviewed paper largely confirming that the urban heat-island effects were minimal, and last year SUNY-Albany dismissed Keenan’s fraud allegations. (Read the Guardian‘s story on this controversy as well as this rebuttal on the RealClimate blog for more.)

But though Keenan may not have succeeded in discrediting past results, he has raised one salient issue: transparency. Today, the general feeling is that climate scientists must be accountable and able to produce backup data upon request, even if to show that their original conclusions still hold.


Who is he? Chief meteorologist at KPAY radio in Northern California and blogger at Watts Up With That? and

Chief beef: Reliability of temperature measurement data

Telling quote: "The reliability of data used to document temperature trends is of great importance in this debate. We can’t know for sure if global warming is a problem if we can’t trust the data." —Is the U.S. Surface Temperature Record Reliable?, 2009

Role: Only in the Internet era could Watts — a local California weatherman and designer of weather monitoring systems — become a prominent voice in an ongoing international policy debate. But his Watts Up With That? (WUWT ) has improbably become one of the world’s most popular climate-change blogs, and an online poll won it a Weblog Award for best science blog in 2008. WUWT passes along tidbits of news on the trials and tribulations of the IPCC, as well as weather events that Watts suggests dispute the conventional wisdom of global warming.

But Watts’s most significant contribution to the global warming debate may be WUWT‘s sister site, After raising concerns about the reliability of the monitoring stations that the National Oceanic and Atmospheric Administration (NOAA) relies on to measure the U.S. surface-temperature data used to show warming over time, Watts began to investigate. NOAA specifies that each station be located far from exhaust fans, asphalt, sidewalks, heat-absorbing buildings, or cities. Using his website, Watts recruited more than 650 volunteers to take photos of these stations around the country and document inconsistencies. According to Watts in a 2009 report documenting his findings, of the 860 stations his team inspected, 89 percent fail to meet NOAA’s site requirements.

The study made Watts something of a star in the climate-skeptic community, earning him national press and television appearances. But Watts never crunched the numbers to determine whether the discrepancies mattered. Several months after Watts’s report was released, several NOAA scientists published a peer-reviewed study (pdf) finding that the stations exhibited an "overall residual negative (‘cool’) bias." Even with the irregularities Watts observed, the authors noted, what mattered was not the spot temperatures but the change over time. Plus, they found, data from only the 70 stations that classified as "good" or better showed warming over time that was similar to the overall data NOAA had been using.

Despite his views on anthropogenic global warming and dislike of environmentalists, Watts claims to be a "green" who drives an electric car and has installed solar panels on his house.


Who is he? Columnist for Britain’s Sunday Telegraph

Chief beef: The anti-capitalist implications of climate change legislation

Telling quote: "If one accepts the thesis that the planet faces a threat unprecedented in history, the implications are mind-boggling. But equally mind-boggling now are the implications of the price we are being asked to pay by our politicians to meet that threat." —Sunday Telegraph, March 25, 2009

Role: With its aggressive muckraking style and demonstrably lower standards for accuracy and fact-checking, the British press has become one of the most effective conduits for the global-warming denying movement. The Times, Telegraph, and Daily Mail highlight and promote often misleading stories that contradict the IPCC line on climate change, feeding back into the U.S. media through right-wing blogs and the Drudge Report (founder Matt Drudge seems to take particular pleasure in posting reports of blizzards during major climate conferences). But no British writer enjoys infuriating the climate establishment with quite as much relish as the Telegraph‘s Booker, whose weekly column has become a must-read for climate skeptics.

It was largely Booker who popularized McIntyre’s critique of the hockey-stick graph and, more recently, the "climategate" scandal. But the IPCC’s failings, both real and imagined, were just icing on the cake for Booker, who had previously declared 2008 "the year climate change was disproved" by low temperatures and record snowfalls (scientists say it takes years of data for a trend to be established). Booker, a history major at Cambridge, also frequently attacks the scientific credentials of the IPCC and particularly those of its chairman, Rajendra Pachauri, a "former railway engineer with no qualifications in climate science." (Pachauri has a dual Ph.D. in industrial engineering and economics from North Carolina State University.)

What really rankles Booker is the millions of pounds spent on efforts to mitigate climate change and the economic effects of environmental legislation. In his 2009 book, The Real Global Warming Disaster, Booker argues that environmental restrictions will destroy the Western way of life and put Europe and the United States at an economic disadvantage to Asian countries that have not bought into the climate hype.

Booker has also touted research arguing that white asbestos is not harmful and disputing that smoking causes cancer. These views have prompted Booker’s frequent adversary — the Guardian‘s Monbiot — to create a "Booker Prize for Bullshit."


Who is he? Contributor for the Telegraph, blogger for EU Referendum, and commentator at the Bruges Group, a Euroskeptic British think tank

Chief beef: Credibility of climate-change proponents

Telling quote: "This is the biggest heist in history. As they poured carbon over snow-covered Denmark from their gas-guzzling jets, world leaders were congratulating themselves on securing a deal which will make their backers and financiers a trillion pounds a year." —The Daily Mail, Dec. 22, 2009

Role: Like his frequent collaborator Christopher Booker, with whom he was co-authored two books and numerous articles, North combines skepticism about climate change with opposition to the European Union and the British welfare state. North — not to be confused with Richard D. North, another right-wing British journalist and climate-change skeptic — worked as a research director at the European Parliament and then emerged as one of the most outspoken critics of EU bureaucracy and the effects of EU integration on British businesses.

He started the EU Referendum blog with fellow Bruges group commentator Helen Szamuely in 2005 with a focus on EU politics. But with the latest controversy over the IPCC, North has begun to focus almost exclusively on climate change. In particular, North has set his sights on IPCC chairman Pachauri, publicizing his ties to India’s Tata group and even the golf course owned by his NGO, the Energy and Resources Institute.

North is generally not particularly concerned with the science behind climate change, and though he links frequently to science-focused bloggers like Anthony Watts, he is more interested in impugning the credibility of the IPCC and climate-change community. "This is not about science but ‘prestige,’" he writes. "The only sure way to destroy the scam is to rob the players of that vital quality, their own ‘prestige.’"


Who is he? Third Viscount Monckton of Brenchley, former political advisor, writer

Chief beef: The "flawed science" behind anthropogenic global warming and the international left’s promotion of it

Telling quote: "The right response to the non-problem of ‘global warming’ is to have the courage to do nothing." —U.S. congressional testimony, March 29, 2009

Role: In his long and controversial career, Lord Monckton has been a journalist, policy advisor in Margaret Thatcher’s government and corporate consultant. Monckton currently serves as policy advisor to the Science and Public Policy Institute, an anti-global-warming think tank based in Virginia. A classics major at Cambridge University, Monckton burst onto the climate-change scene in 2006 with a lengthy two-part series in the Daily Telegraph written in response to the Stern Review, the British government’s commissioned report on the economic effects of climate change. Monckton disputed the IPCC’s assessment of the science, pointing to what he said were flaws in the controversial "hockey-stick graph." ("There is scarcely a line in Lord Monckton’s paper which is not wildly wrong," the Guardian‘s environmental correspondent George Monbiot responded, and Gavin Schmidt of NASA’s Goddard Institute called it "cuckoo science.")

Monckton has since become one of the most popular speakers on the subject, traveling around the world to give his own version of Gore’s slide-show presentation from An Inconvenient Truth. Monckton has repeatedly challenged the former U.S. vice president to a public debate on climate change, which Gore has so far refused to accept. In 2009, Monckton was invited as an expert witness to testify before the U.S. House Subcommittee on Energy and the Environment.

Monckton went into overdrive before the U.N. summit in Copenhagen, arguing that U.S. President Barack Obama was planning to sign away U.S. sovereignty and that a "world government is going to be created" by the international agreement. Monckton traveled to Copenhagen, speaking on the margins of the conference. As usual, he managed to attract controversy, this time by comparing environmental protesters to "Hitler Youth."

Christina Larson is an award-winning foreign correspondent and science journalist based in Beijing, and a former Foreign Policy editor. She has reported from nearly a dozen countries in Asia. Her features have appeared in the New York Times, Wired, Science, Scientific American, the Atlantic, and other publications. In 2016, she won the Overseas Press Club of America’s Morton Frank Award for international magazine writing. Twitter: @larsonchristina

Joshua Keating was an associate editor at Foreign Policy. Twitter: @joshuakeating

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