Scientists opposing the mainstream scientific assessment of global warming

From Wikipedia, the free encyclopedia

This article lists scientists who have expressed doubt regarding the current scientific opinion on global warming. The mainstream position of the climate science community has been summarized in the 2001 Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) as follows:

The global average surface temperature has risen 0.6 ± 0.2 °C since the late 19th century, and 0.17 °C per decade in the last 30 years. [1]
"There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities", in particular emissions of the greenhouse gases carbon dioxide and methane. [2]
If greenhouse gas emissions continue the warming will also continue, with temperatures increasing by 1.4 °C to 5.8 °C between 1990 and 2100. Accompanying this temperature increase will be a sea level rise of 9 cm to 88 cm, and increases in some types of extreme weather. On balance the impacts of global warming will be significantly negative, especially for larger values of warming. [3]

While the first point is now accepted by virtually all climate scientists, a small number of scientists—relative to the number supporting the mainstream view—actively disagree with the second or third points. This article lists scientists who have, since the Third Assessment Report, published research or made public comments opposing at least one of the conclusions listed above.

Scientists listed here have at some time published at least one peer-reviewed article in the broad area of natural sciences, though not necessarily in a field related to climate. For a general list including non-scientists, see global warming skeptics. Inclusion is based on specific, attributable statements in a scientist's own words, and not on listings in petitions or surveys.

In February 2007, the IPCC released a summary of a Fourth Assessment Report. Dissent reported by this article is based on reaction to the Third Assessment Report, until public comments on the full Fourth Assessment Report are broadly available.

1 The cause of global warming is unknown
2 Global warming is mostly due to natural processes
3 Climate forecasting isn't as accurate as the IPCC ranges imply
4 Global warming is good for human society
5 See also
6 External links

[edit] The cause of global warming is unknown

Scientists in this section conclude it is too early to ascribe any cause to the observed rising temperatures, man-made or natural.

Claude Allègre, geophysicist, Institute of Geophysics (Paris): "The increase in the CO₂ content of the atmosphere is an observed fact and mankind is most certainly responsible. In the long term, this increase will without doubt become harmful, but its exact role in the climate is less clear. Various parameters appear more important than CO₂. Consider the water cycle and formation of various types of clouds, and the complex effects of industrial or agricultural dust. Or fluctuations of the intensity of the solar radiation on annual and century scale, which seem better correlated with heating effects than the variations of CO₂ content." (Translation from the original French version in L'Express, May 10, 2006 [4])
Robert C. Balling, Jr., director of the Office of Climatology and a professor of geography at Arizona State University: "[I]t is very likely that the recent upward trend [in global surface temperature] is very real and that the upward signal is greater than any noise introduced from uncertainties in the record. However, the general error is most likely to be in the warming direction, with a maximum possible (though unlikely) value of 0.3 °C. ... At this moment in time we know only that: (1) Global surface temperatures have risen in recent decades. (2) Mid-tropospheric temperatures have warmed little over the same period. (3) This difference is not consistent with predictions from numerical climate models." (George C. Marshall Institute, Policy Outlook, September 2003[5])
Chris de Freitas, Associate Professor, School of Geography, Geology and Environmental Science, University of Auckland: "There is evidence of global warming. ... But warming does not confirm that carbon dioxide is causing it. Climate is always warming or cooling. There are natural variability theories of warming. To support the argument that carbon dioxide is causing it, the evidence would have to distinguish between human-caused and natural warming. This has not been done." (The New Zealand Herald, May 9, 2006 [6])
David Deming, geology professor at the University of Oklahoma: "The amount of climatic warming that has taken place in the past 150 years is poorly constrained, and its cause--human or natural--is unknown. There is no sound scientific basis for predicting future climate change with any degree of certainty. If the climate does warm, it is likely to be beneficial to humanity rather than harmful. In my opinion, it would be foolish to establish national energy policy on the basis of misinformation and irrational hysteria." (Testimony before the U.S. Senate Committee on Environment and Public Works, December 6, 2006 [7])
Richard Lindzen, MIT meteorology professor and member of the National Academy of Sciences: "We are quite confident (1) that global mean temperature is about 0.5 °C higher than it was a century ago; (2) that atmospheric levels of CO₂ have risen over the past two centuries; and (3) that CO₂ is a greenhouse gas whose increase is likely to warm the earth (one of many, the most important being water vapor and clouds). But--and I cannot stress this enough--we are not in a position to confidently attribute past climate change to CO₂ or to forecast what the climate will be in the future." [8] "[T]here has been no question whatsoever that CO₂ is an infrared absorber (i.e., a greenhouse gas — albeit a minor one), and its increase should theoretically contribute to warming. Indeed, if all else were kept equal, the increase in CO₂ should have led to somewhat more warming than has been observed." (San Francisco Examiner, July 12, 2006 [9] and in Wall Street Journal, June 26, 2006, Page A14)
Roy Spencer, principal research scientist, University of Alabama in Huntsville: "We need to find out how much of the warming we are seeing could be due to mankind, because I still maintain we have no idea how much you can attribute to mankind." (George C. Marshall Institute Washington Roundtable on Science and Public Policy, April 17, 2006 [10])

[edit] Global warming is mostly due to natural processes

Scientists in this section conclude that natural causes are likely more to blame than human activities for the observed rising temperatures.

Khabibullo Ismailovich Abdusamatov, at Pulkovskaya Observatory of the Russian Academy of Sciences and the supervisor of the Astrometria project of the Russian section of the International Space Station: "Global warming results not from the emission of greenhouse gases into the atmosphere, but from an unusually high level of solar radiation and a lengthy - almost throughout the last century - growth in its intensity." (Russian News & Information Agency, Jan. 15, 2007 [11]) (See also [12], [13], [14])
Sallie Baliunas, astronomer, Harvard-Smithsonian Center for Astrophysics: "[T]he recent warming trend in the surface temperature record cannot be caused by the increase of human-made greenhouse gases in the air." [15] In 2003 Baliunas and Soon wrote that "there is no reliable evidence for increased severity or frequency of storms, droughts, or floods that can be related to the air’s increased greenhouse gas content." [16]
Robert M. Carter, geologist, researcher at the Marine Geophysical Laboratory at James Cook University in Australia: "The essence of the issue is this. Climate changes naturally all the time, partly in predictable cycles, and partly in unpredictable shorter rhythms and rapid episodic shifts, some of the causes of which remain unknown." (Telegraph, April 9, 2006 [17])
George V. Chilingar, Professor of Civil and Petroleum Engineering at the University of Southern California, and Leonid F. Khilyuk: "The authors identify and describe the following global forces of nature driving the Earth’s climate: (1) solar radiation ..., (2) outgassing as a major supplier of gases to the World Ocean and the atmosphere, and, possibly, (3) microbial activities ... . The writers provide quantitative estimates of the scope and extent of their corresponding effects on the Earth’s climate [and] show that the human-induced climatic changes are negligible." (Environmental Geology, vol. 50 no. 6, August 2006 [18])
Ian Clark, hydrogeologist, professor, Department of Earth Sciences, University of Ottawa: "That portion of the scientific community that attributes climate warming to CO₂ relies on the hypothesis that increasing CO₂, which is in fact a minor greenhouse gas, triggers a much larger water vapour response to warm the atmosphere. This mechanism has never been tested scientifically beyond the mathematical models that predict extensive warming, and are confounded by the complexity of cloud formation - which has a cooling effect. ... We know that [the sun] was responsible for climate change in the past, and so is clearly going to play the lead role in present and future climate change. And interestingly... solar activity has recently begun a downward cycle." (The Hill Times, March 22, 2004 [19])
Lee C. Gerhard, formerly Principal Geologist of the Kansas Geological Survey[20], currently with oil and gas explorationists Thomasson Partner Associates, Inc.[21]: "There is no clear discernible effect of human activities on global temperature: [22]
William M. Gray, Professor of Atmospheric Science, Colorado State University: "This small warming is likely a result of the natural alterations in global ocean currents which are driven by ocean salinity variations. Ocean circulation variations are as yet little understood. Human kind has little or nothing to do with the recent temperature changes. We are not that influential." (BBC News, 16 Nov 2000 [23]) "I am of the opinion that [global warming] is one of the greatest hoaxes ever perpetrated on the American people." (Washington Post, May 28, 2006 [24]) "So many people have a vested interest in this global-warming thing—all these big labs and research and stuff. The idea is to frighten the public, to get money to study it more." (Discover, vol. 26 no. 9, September 2005 [25])
Zbigniew Jaworowski, chair of the Scientific Council at the Central Laboratory for Radiological Protection in Warsaw: "The atmospheric temperature variations do not follow the changes in the concentrations of CO₂ ... climate change fluctuations comes ... from cosmic radiation." (21st Century Science & Technology, Winter 2003-2004, p. 52-65 [26])
Martin Keeley [27], self-described "Wealth Creator and Entrepreneur", Director of oil and gas exploration consultancy Fieldco International Ltd.: "I have come across no rigorous proof that wasteful human pollution has caused any significant climate change. ... The only proof of anthropogenic climate change ever offered, which to my mind is fallacious, is that temperature has increased with Western industrialisation. ... Global warming is indeed a scam, perpetrated by scientists with vested interests, but in need of crash courses in geology, logic and the philosophy of science." (BBC News, December 6, 2004 [28])
David Legates, associate professor of geography and director of the Center for Climatic Research, University of Delaware: "About half of the warming during the 20th century occurred prior to the 1940s, and natural variability accounts for all or nearly all of the warming." (May 15, 2006 [29])
Marcel Leroux, former Professor of Climatology, Université Jean Moulin: "The possible causes, then, of climate change are: well-established orbital parameters on the palaeoclimatic scale, ... solar activity, ...; volcanism ...; and far at the rear, the greenhouse effect, and in particular that caused by water vapor, the extent of its influence being unknown. These factors are working together all the time, and it seems difficult to unravel the relative importance of their respective influences upon climatic evolution. Equally, it is tendentious to highlight the anthropic factor, which is, clearly, the least credible among all those previously mentioned." (M. Leroux, Global Warming - Myth or Reality?, 2005, p. 120 [30])
Tim Patterson [31], paleoclimatologist and Professor of Geology at Carleton University in Canada: "There is no meaningful correlation between CO₂ levels and Earth's temperature over this [geologic] time frame. In fact, when CO₂ levels were over ten times higher than they are now, about 450 million years ago, the planet was in the depths of the absolute coldest period in the last half billion years. On the basis of this evidence, how could anyone still believe that the recent relatively small increase in CO₂ levels would be the major cause of the past century's modest warming?" [32]
Frederick Seitz, retired, former solid-state physicist, former president of the National Academy of Sciences: "So we see that the scientific facts indicate that all the temperature changes observed in the last 100 years were largely natural changes and were not caused by carbon dioxide produced in human activities." (Environment News, 2001 [33])
Nir Shaviv, astrophysicist at the Hebrew University of Jerusalem: "[T]he truth is probably somewhere in between [the common view and that of skeptics], with natural causes probably being more important over the past century, whereas anthropogenic causes will probably be more dominant over the next century. ... [A]bout 2/3's (give or take a third or so) of the warming [over the past century] should be attributed to increased solar activity and the remaining to anthropogenic causes." His opinion is based on some proxies of solar activity over the past few centuries. [34]
Fred Singer, Professor emeritus of Environmental Sciences at the University of Virginia: "The greenhouse effect is real. However, the effect is minute, insignificant, and very difficult to detect." (Christian Science Monitor, April 22, 2005) [35] "The Earth currently is experiencing a warming trend, but there is scientific evidence that human activities have little to do with it.", NCPA Study No. 279, Sep. 2005 [36]. “It’s not automatically true that warming is bad, I happen to believe that warming is good, and so do many economists.” (CBC's Denial machine @ 19:23 - Google Video Link)
Willie Soon, Harvard-Smithsonian Center for Astrophysics: "[T]here's increasingly strong evidence that previous research conclusions, including those of the United Nations and the United States government concerning 20th century warming, may have been biased by underestimation of natural climate variations. The bottom line is that if these variations are indeed proven true, then, yes, natural climate fluctuations could be a dominant factor in the recent warming. In other words, natural factors could be more important than previously assumed." (Harvard University Gazette, 24 April 2003 [37])
Philip Stott, professor emeritus of biogeography at the University of London: "...the myth is starting to implode. ... Serious new research at The Max Planck Institute has indicated that the sun is a far more significant factor..." (Global Warming as Myth [38])
Henrik Svensmark, Danish National Space Center: "Our team ... has discovered that the relatively few cosmic rays that reach sea-level play a big part in the everyday weather. They help to make low-level clouds, which largely regulate the Earth’s surface temperature. During the 20th Century the influx of cosmic rays decreased and the resulting reduction of cloudiness allowed the world to warm up. ... most of the warming during the 20th Century can be explained by a reduction in low cloud cover." [39]
Jan Veizer, environmental geochemist, Professor Emeritus from University of Ottawa: "At this stage, two scenarios of potential human impact on climate appear feasible: (1) the standard IPCC model ..., and (2) the alternative model that argues for celestial phenomena as the principal climate driver. ... Models and empirical observations are both indispensable tools of science, yet when discrepancies arise, observations should carry greater weight than theory. If so, the multitude of empirical observations favours celestial phenomena as the most important driver of terrestrial climate on most time scales, but time will be the final judge." (In J. Veizer, "Celestial climate driver: a perspective from four billion years of the carbon cycle", Geoscience Canada, March, 2005. [40], [41])

[edit] Climate forecasting isn't as accurate as the IPCC ranges imply

Scientists in this section conclude that it isn't possible to predict global climate accurately enough to justify the narrowness of the ranges projected for temperature and sea-level rise over the next century. These scientists don't specifically conclude that the numbers are too high, or specifically conclude that the numbers are too low, merely that the numbers are likely to be inaccurate in either direction due to the difficulty of global climate modeling.

Orrin Pilkey, coastal geologist and emeritus professor at Duke University, and Linda Pilkey-Jarvis: "Assumption upon assumption, uncertainty upon uncertainty, and simplification upon simplification are combined to give an ultimate and inevitably shaky answer, which is then scaled up beyond the persistence time to make long-term predictions of the future of sea-level rise. Aside from the frailty of assumptions, there remains ordering complexity: the lack of understanding of the timing and intensity of each variable. ... The objectivity of the IPCC documents is laudable. But the fact that the group recognizes its model weaknesses and is trying to improve them doesn't make its conclusions stronger or more believable." (Pilkey and Pilkey-Jarvis, Useless Arithmetic: Why Environmental Scientists Can’t Predict the Future [42] [43], pps. 82-83)
Valerio Lucarini, Research Associate at the Department of Mathematics and Computer Science, University of Camerino, and Project Director of HYDROCARE : "The presence of structural uncertainties (due to the choices made when a model is built on which processes and feedbacks are described and how they are described) and of parametric uncertainties (due to the lack of knowledge on quantities which characterize the climatic system), implies that every model used to generate projections about future climate change is a priori false, or better, weak in its descriptive power." (Lucarini, V. (2002) Towards a definition of climate science, Int. J. Environment and Pollution, Vol. 18, No. 5 [44])
Hendrik Tennekes, retired Director of Research, Royal Netherlands Meteorological Institute: "The blind adherence to the harebrained idea that climate models can generate 'realistic' simulations of climate is the principal reason why I remain a climate skeptic. From my background in turbulence I look forward with grim anticipation to the day that climate models will run with a horizontal resolution of less than a kilometer. The horrible predictability problems of turbulent flows then will descend on climate science with a vengeance." [45]

[edit] Global warming is good for human society

Scientists in this section conclude that the rising temperatures that are occurring will be of little impact or a net positive for human society.

Sherwood Idso, former research physicist, USDA Water Conservation Laboratory, and adjunct professor, Arizona State University: "[W]arming has been shown to positively impact human health, while atmospheric CO₂ enrichment has been shown to enhance the health-promoting properties of the food we eat, as well as stimulate the production of more of it. ... [W]e have nothing to fear from increasing concentrations of atmospheric CO₂ and global warming." ("Enhanced or Impaired? Human Health in a CO2-Enriched Warmer World", co2science.org, Nov, 2003, p. 30 [46])