List of scientists opposing global warming consensus

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This page lists scientists, not necessarily involved in climate research, who have expressed doubt regarding the scientific opinion on global warming. The consensus has been summarized by the UN 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 continue and indeed accelerate, with temperatures increasing by 1.4°C to 5.8°C between 1990 and 2100, causing sea level rise and increasing extreme weather events like hurricanes. On balance, the impacts of global warming will be significantly negative. [3]

These main points are held by the majority of climate scientists and those doing research in closely related fields; however, there are also a small number of scientists who actively disagree. This page is intended to highlight those scientists who have, since the 2001 IPCC Third Assessment Report, published research or made public comments openly opposing at least one of the conclusions listed above.

Only scientists with a record of scholarship are included, and they must have been making specific statements, not merely participating in a poll or survey of opinion (for a general list including non-scientists, see global warming skeptics). This list is intended to be comprehensive, but is likely to be incomplete.

1 The Earth is not warming
2 The Earth is warming but the cause is unknown
3 The Earth is warming but mostly due to natural processes
4 Global warming is good for human society
5 See also
6 External links

[edit] The Earth is not warming

Since 2001, no climate scientists have expressed skepticism that warming, of the magnitude described by the IPCC, has occurred.

[edit] The Earth is warming but the cause is unknown

Scientists in this section accept the observations of rising temperatures, but conclude it is too early to ascribe any cause to these changes, man-made or natural.

Richard Lindzen, MIT meteorology professor and member of the National Academy of Sciences: "We are quite confident that [the] global mean temperature is about 0.5 degrees Celsius higher than it was a century ago… [but] we are not in a position to confidently attribute past climate change to carbon dioxide or to forecast what the climate will be in the future..." [4]. He has also said "Indeed, if all else were kept equal, the increase in carbon dioxide should have led to somewhat more warming than has been observed." [5] (Also in WSJ, June 26, 2006, Page A14)
Robert C. Balling, Jr., director of the Office of Climatology and an associate 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 [6]
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 & PUBLIC POLICY, Satellite Temperature Data, March 2006 [7]
David Deming, University of Oklahoma and Oklahoma Council of Public Affairs "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."[8]
Claude Allegre, French geophysicist, writes: “In all likelihood, there is a climate change, but the latter is characterized more by sudden shifts, both in space and time (the heat wave or the “rotten summer”, just like the violent tornadoes or the increased frequency of floods, are examples of these) than by global warming. The cause of this climate change is unknown. Is it man? Is it nature?” [9]

[edit] The Earth is warming but mostly due to natural processes

Scientists in this section accept the observations of rising temperature, but conclude that natural causes may be more to blame than human activities.

William M. Gray, 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 [10]) "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 [11])
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 [12])
Sallie Baliunas, 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." [13] 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." [14]
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 [15]
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. [16]
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) [17] "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 [18].
Robert M. Carter, 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." [19]
Tim Patterson [20], 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?" [21]
Jan Veizer, Professor Emeritus, University of Ottawa: "At this stage, two scenarios of potential human impact on climate appear feasible: (1) the standard IPCC model that advocates the leading role of greenhouse gases, particularly of CO₂, 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. [22])
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 [23])
Leonid F. Khilyuk and George V. Chilingar, professor of civil and petroleum engineering at the University of Southern California write: "The writers provide quantitative estimates of the scope and extent of their corresponding effects on the Earth’s climate. Quantitative comparison of the scope and extent of the forces of nature and anthropogenic influences on the Earth’s climate is especially important at the time of broad-scale public debates on current global warming. The writers show that the human-induced climatic changes are negligible." [24]
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." [25]

[edit] Global warming is good for human society

This section contains scientists who accept that global warming will occur, but advocate the position that it will be of little impact or a net positive for human society.

Sherwood Idso, President Center for the Study of Carbon Dioxide and Global Change, formerly a research physicist at the 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 ([26]).
Fred Singer, Professor emeritus of Environmental Sciences at the University of Virginia: “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)