Last week the libertarian Heartland Institute held its 6^th “International Conference on Climate Change” in Washington, DC, bringing together a varied batch of vocal climate contrarians to rail against the scientific consensus that human-induced climate change is a serious problem.

The speakers seemed to be more united by political ideology and a common enemy than by their grievances about the science. Among their assertions:

• “CO2 was found guilty in contradiction to the evidence because as we are now all aware, the temperature changes before the CO2, it is not the other way around, as is the fundamental assumption that is made for the AGW.” -- Tim Ball
• “I agree with the IPCC that adding CO2 to the atmosphere should cause some warming. Where we differ is the degree of warming.” -- Roy Spencer
• “I believe that this warming shown here [after 1979] is not real, does not exist.” -- Fred Singer
• “From the mid-1970s,” the earth warmed ".17 degrees C per decade in the surface record, .14 degrees in the satellite record." -- Pat Michaels
• “I do not agree” that “the recent rise in atmospheric carbon dioxide is due to man.” -- Steve Goreham
• “There's no question that CO2 is increasing in the atmosphere and that the primary cause is human.” -- Fred Singer

Heartland senior fellow James Taylor claimed that the event is about “getting the science out to people,” but several of the speakers indicated that this is by no means your typical scientific conference (if the repeated Atlas Shrugged references didn't give that away):

• “I guess I'm not a climate skeptic, just an economist. I don't know enough about the climate science to be skeptical about it.” -- Robert Mendelsohn
• “I'm a lawyer, not a climate scientist.” -- Barry Brill
• “I'm not a climate scientist. ... I'm a space guy.” -- Larry Bell
• “I'm just a layperson ... I'm also a relative newcomer to the climate battle.” -- Steve Goreham
• “I feel a bit of an imposter talking about the science. I'm kind of -- I'm not a scientist, you may be aware. ... I leave the science stuff to you guys and I think it's good that we stick to our jobs.” -- James Delingpole

One of the attendees complained to me that the media would ignore the conference because it doesn't fit the preferred narrative. As it turned out, the New York Times posted an uncritical Greenwire article about the event before it had even ended, which Heartland president Joseph Bast then praised as “really nice” and “balanced.”

But Heartland doesn't need the news media to cover these events. The endgame is increased visibility of those who challenge the global warming consensus and there's evidence that this endeavor has been successful.

Maxwell Boykoff of the Center for Science and Technology Policy Research at the University of Colorado has noted that on the issue of climate change, “Outlier voices have gained more prominence and traction in mass media over time through a mix of political economic, cultural, and social factors. Moreover, institutional workings of mass media - such as journalistic norms, values and practices - can contribute to such patterns.”

Indeed, with regard to media coverage of climate change, one's expertise is often a weak predictor of the attention given them. Take, for instance atmospheric scientist Scott Denning, the only speaker at the conference who presented what the Heartland Institute called the “warmist case.” (While other mainstream climate scientists have hesitated to accept Heartland's invitation, Denning contends that “strong and persuasive engagement” is necessary.)

Denning has published 36 peer-reviewed climate articles since 2007. According to a search of articles/segments mentioning “global warming” or “climate change” in the New York Times, Los Angeles Times, Wall Street Journal, Washington Post, USA Today, Associated Press, Fox News, CNN, MSNBC, NBC, CBS, and ABC, and NPR, Denning has been quoted or hosted only twice since 2007: In February 2009 AP articles on the NASA satellite that malfunctioned.

The following chart shows how Denning, a strong communicator who says he is “very responsive” to media requests, compares to two other speakers at the conference: Climatologist Pat Michaels of the libertarian Cato Institute, who delivered the keynote address and has received funding from fossil fuel interests for decades, and Chris Horner of the libertarian Competitive Enterprise Institute, who is not a scientist but often comments on climate science in media appearances:

Fox News accounted for 13 of Michaels' appearances and 34 of Horner's appearances. Denning says he has never been invited to speak about climate change on Fox News.

This is not to say that most climate contrarians garner this level of media attention or that news outlets ignore highly-qualified mainstream scientists (though I'd argue that Fox News does.) But clearly, media-savvy individuals with outlier views on climate change can be disproportionally represented in the national news media regardless of the level of their expertise.

HEARTLAND INSTITUTE STRIVES TO CLOUD THE CONSENSUS

Heartland president Joseph Bast acknowledged at the conference that “the main motivation, frankly, for the Heartland Institute being involved in this debate” is to prevent the U.S. government from adopting policies that favor renewable energy, which he claims would cause an “economic disaster for the country.” (But it's the other guys who are “alarmist.”) In other words, the organization approaches the science with a policy agenda already determined, making Heartland an unlikely champion of “Restoring the Scientific Method,” which was the theme of the conference.

In his closing remarks, Bast said: “I am absolutely convinced that if you open the hood and look at the science on climate change, you're going to come away convinced that the science is very sketchy, very uncertain, and as a result it doesn't justify the kind of public policies that are being advanced.”

In the interest of forestalling government action designed to reduce fossil fuel use, the Heartland Institute seeks to popularize the message that “the mainstream of the scientific community ... does not believe that global warming is a crisis.” The media is certainly among the intended recipients of this message. But the five sources Heartland's website cites support this claim are not persuasive:

1. HEARTLAND CLAIM: “Since 2007, more than 31,072 American scientists, including 9,021 with Ph.Ds, have signed the a petition which says, in part, 'There is no convincing scientific evidence that human release of carbon dioxide, methane, or other greenhouse gases is causing or will, in the foreseeable future, cause catastrophic heating of the Earth's atmosphere and disruption of the Earth's climate.'”

• REALITY: This petition actually dates back to 1998, not 2007. Organized by chemist and failed 2010 Republican Congressional candidate Art Robinson, it does not tell us anything about the consensus on global warming because, as Gary Whittenberger wrote in Skeptic magazine, a consensus is not “defined by some large absolute number of persons.” Rather, “It is determined by a large percentage of persons in a relevant sample,” and Robinson's petition “reports neither the total number of persons to whom he sent petition cards in the first place nor the number of persons to whom he sent petition cards who subsequently returned only messages of disagreement.” The petition defined as a “scientist” anyone who claims to have at least a bachelor's degree in a variety of fields including math, medicine and engineering. Only 12 percent of the signatories hold degrees in “atmosphere, earth & environment” according to the petition's website, and no information is given on how many of those individuals are active scientists, how many have advanced degrees, or how many have actually conducted research related to climate change. The names and degrees have not been independently confirmed and Robinson acknowledged that fake names have made their way onto the petition.

2. HEARTLAND CLAIM: "A 2003 international survey of climate scientists (with 530 responding) found only 9.4 percent 'strongly agreed' and 25.3 percent 'agreed' with the statement 'climate change is mostly the result of anthropogenic causes.' Some 10.2 percent “strongly disagreed.'”

• REALITY: It's notable that Heartland cites this 8-year-old survey by Hans von Storch and Dennis Bray, who have since released a more recent survey. More importantly, Bray and von Storch have acknowledged that the 2003 survey question was “problem[atic]” because it did not distinguish between current or future climate change and climate change in general, which has obviously been driven by non-human forces in the past:

[T]he question refers to “climate change” in general. We intended to ask for responses to the statement “Ongoing climate change is mostly the result of anthropogenic causes”, but some respondents may have considered Holocene climate change in general. Thus, “disagreement” with the statement does not necessarily signal doubt about the perspective of a dominantly man-made climate change in the coming decades, but it mostly reveals an assessment of presently emerging climate change. The problem is that some commentators interpret our numbers as responses to “Future climate change is mostly the result of anthropogenic causes.”

Additionally, Heartland incorrectly suggests that respondents were given the options “agree” and “strongly agree,” when in fact, they were presented with a scale from 1 (strongly agree) to 7 (strongly disagree). Heartland only provided the results from 1, 2, and 7.

3. HEARTLAND CLAIM: "A 2006 survey of scientists in the U.S. found 41 percent disagreed that the planet's recent warmth 'can be, in large part, attributed to human activity,' and 71 percent disagreed that recent hurricane activity is significantly attributable to human activity."

• REALITY: This is not a “survey of scientists” but rather a survey of “environmental practitioners,” defined as “those who implement environmental policies and regulations for government and industry.” The survey found that “59 percent respond that current climatic activity exceeding norms calibrated by over 100 years of weather data collection can be, in large part, attributed to human activity.” It also found that “76 percent believe it important to include tighter controls of greenhouse gases such as carbon and methane in future U.S. environmental regulations.”

4. HEARTLAND CLAIM: "A recent review of 1,117 abstracts of scientific journal articles on 'global climate change' found only 13 (1 percent) explicitly endorse the 'consensus view' while 34 reject or cast doubt on the view that human activity has been the main driver of warming over the past 50 years."

• REALITY: Anthropologist Benny Peiser, the author of this “review,” has since admitted that “some of the abstracts that I included in the 34 'reject or doubt' category are very ambiguous and should not have been included.” Demonstrating that his review cannot inform on the status of the consensus, Peisner said that “the vast majority of papers published on global warming” were not included. In contradiction to the Heartland Institute's claim, he also acknowledged that “the overwhelming majority of climatologists is agreed that the current warming period is mostly due to human impact,” while maintaining that it is not “unanimous.”

5. HEARTLAND CLAIM: "In June 2009, the Nongovernmental International Panel on Climate Change (NIPCC) released an 880-page report, titled Climate Change Reconsidered, that presented the first comprehensive rebuttal of the reports of the United Nations' Intergovernmental Panel on Climate Change (IPCC). With contributions from more than 30 scientists and citations to more than 4,000 peer-reviewed studies, the NIPCC report concluded that climate change is not a crisis."

• REALITY: This report was published by the Heartland Institute and says nothing about the views of “the mainstream of the scientific community.” The lead authors of the report are retired physicist S. Fred Singer and geographer Craig Idso, and both previously worked with fossil fuel companies. Climate scientists commenting on the NIPCC report have said it is "dishonest" and makes "some embarrassing mistakes in basic logic."

PUBLIC CONFUSED ABOUT VIEWS OF SCIENTISTS

Although the evidence provided by the Heartland Institute is not robust, their message appears to have gained traction, with significant chunks of the American population unaware of the extent to which scientists agree that human-induced climate change is happening.

In a November 2009 Associated Press survey, 66 percent of respondents said “there is a lot of disagreement among scientists” about “whether or not global warming is happening.” Sixty-seven percent also said “there is a long of disagreement among scientists” about “the causes of global warming.”

Gallup also reported on March 11, 2010 that “The percentage of Americans who think most scientists believe global warming is occurring has dropped 13 points from two years ago, and is the lowest since the first time Gallup asked this question back in 1997.”

And a nationwide poll conducted in May 2010 by Virginia Commonwealth University found that only 37% “believe the evidence is widely accepted in the scientific community”:

Perceptions of scientific consensus about global warming lean to the view that scientists are divided over global warming. A plurality (49%) believes that many scientists have serious doubts about the evidence on global warming; 37% believe the evidence is widely accepted in the scientific community.

Not surprisingly, beliefs about global warming and scientific consensus are linked. Among those skeptical about global warming 71% say many scientists have doubts about the evidence on global warming, 17% think there is scientific consensus on this. Similarly, among those who believe global warming is mostly due to natural causes 67% say that many scientists have doubts about the evidence on global warming and 19% think there is scientific consensus. Among those who believe global warming is due to human causes the opposite pattern occurs; 57% of this group says the evidence on global warming is widely accepted in the scientific community while about a third (32%) think that many scientists have serious doubts about the evidence on global warming.

The University of Maryland also reported in a December 2010 poll that “a substantial 45% of voters thought that most scientists think climate change is not occurring (12%) or scientists are evenly divided (33%). Fifty-four percent recognized that most scientists think that climate change is occurring.”

(The poll also found that “those who watched Fox News almost daily were significantly more likely [by 30 points] than those who never watched it” to reject the notion that most scientists think climate change is occurring. The poll further stated that “these effects increased incrementally with increasing levels of exposure” to Fox News.)

The most recent poll, a May 2011 Yale/George Mason University survey, found that 40 percent of respondents think “there is a lot of disagreement among scientists about whether or not global warming is happening.” Only thirty-nine percent said “most scientists think global warming is happening.”

CREDIBLE SURVEYS SHOW VAST MAJORITY OF CLIMATE SCIENTISTS AGREE HUMANS ARE CHANGING THE CLIMATE

Many efforts have been made in recent years to guage the level of agreement among scientists about climate change.

According to a 2007 George Mason University survey of scientists belonging to the American Meteorological Society and the American Geophysical Union, “Eighty-four percent say they personally believe human-induced warming is occurring.”

Dennis Bray and Hans von Storch of Germany's Institute for Coastal Research conducted an international survey of climate scientists in 2008 and asked, “How convinced are you that most of recent or near future climate change is, or will be, a result of anthropogenic causes?” Eighty-four percent answered either 5, 6 or 7 on a scale of 1 (not at all) to 7 (very much). The scientists were also asked, “Over the issue of climate change, the general public should be told to be” unconcerned (1) or very worried (7). Eighty-four percent answered 5, 6, or 7. Only 5 percent answered 1, 2, or 3.

In July 2009, the Pew Research Center for the People & the Press released a report compiling data from public opinion polls and a survey of over 2,500 scientists belonging to the American Association for the Advancement of Science, the “world's largest general scientific society.” The report stated:

[T]he near consensus among scientists about global warming is not mirrored in the general public. While 84% of scientists say the earth is getting warmer because of human activity such as burning fossil fuels, just 49% of the public agrees.

A 2009 survey published by the American Geophysical Union also found that of over 3,000 Earth scientists, 90 percent said average global temperatures have risen compared with pre-1800s levels and 82 percent said human activity is a “significant contributing factor” in that trend. The study further concluded that “as the level of active research and specialization in climate science increases, so does agreement with the two primary questions.” Of those who specialize in climate science, 97.4% (75 or 77) said human activity is contributing to rising global temperatures.

The following scientific bodies have also issued statements recognizing the strong body of evidence supporting anthropogenic climate change:

• U.S. National Academy of Sciences: “The scientific understanding of climate change is now sufficiently clear to justify nations taking prompt action.”

• U.S. National Research Council: "[T]he preponderance of scientific evidence points to human activities -- especially the release of carbon dioxide and other greenhouse gases into the atmosphere -- as the most likely cause for most of the global warming that has occurred over the last several decades."

• American Association for the Advancement of Science: “The vast preponderance of evidence, based on years of research conducted by a wide array of different investigators at many institutions, clearly indicates that global climate change is real, it is caused largely by human activities, and the need to take action is urgent.”

• American Chemical Society: "[C]omprehensive scientific assessments of our current and potential future climates clearly indicate that climate change is real, largely attributable to emissions from human activities, and potentially a very serious problem.

• American Physical Society: “The evidence is incontrovertible: Global warming is occurring. If no mitigating actions are taken, significant disruptions in the Earth's physical and ecological systems, social systems, security and human health are likely to occur.”

• American Geophysical Union: “With climate change, as with ozone depletion, the human footprint on Earth is apparent.”

• Geological Society of America: “Concurs with assessments by the National Academies of Science (2005), the National Research Council (2006), and the Intergovernmental Panel on Climate Change (IPCC, 2007) that global climate has warmed and that human activities (mainly greenhouse-gas emissions) account for most of the warming since the middle 1900s.”

• American Meteorological Society: “Despite the uncertainties noted above, there is adequate evidence from observations and interpretations of climate simulations to conclude that the atmosphere, ocean, and land surface are warming; that humans have significantly contributed to this change; and that further climate change will continue to have important impacts on human societies, on economies, on ecosystems, and on wildlife through the 21st century and beyond.”

• American Medical Association: “Scientific evidence shows that the world's climate is changing and that the results have public health consequences.”