This article lists living and deceased scientists who have made statements that conflict with the mainstream assessment of global warming as summarized by the
Intergovernmental Panel on Climate Change and endorsed by other scientific bodies.
If greenhouse gas emissions continue the warming will also continue, with temperatures projected to increase by 1.4 °C to 5.8 °C between 1990 and 2100. Accompanying this temperature increase will be increases in some types of extreme weather and a projected
sea level rise of 9 cm to 88 cm, excluding "uncertainty relating to ice dynamical changes in the West Antarctic ice sheet". On balance the impacts of global warming will be significantly negative, especially for larger values of warming.[3]
This article is an attempt to list scientists who have made statements in disagreement with one or more of the principal conclusions of the Third (or Fourth) Assessment Report of the IPCC. Inclusion is based on the following specific criteria:
For the purposes of this list, qualification as a scientist is reached by publication of at least one peer-reviewed article in their lifetime in a broadly construed area of "natural sciences". The article need not have been written in recent years nor be in a field relevant to climate.
Attributable statements of disagreement in any venue in the individual's own words (not merely inclusion on petitions, surveys, or lists).
Scientists are listed with a recent quote which is representative of their views on climate change. The quote does not necessarily give details of all the nuances of their views on climate change. More detail can usually be found in the main article for that scientist.
Do not agree: global average surface temperature has risen 0.6 ± 0.2 °C since the late 19th century
There are currently no scientists listed in this category.
Do not agree: global average surface temperature has risen 0.17 °C per decade in the period 1970-2000
There are currently no scientists listed in this category.
Do not agree: most of the warming observed in the period 1950-2000 is attributable to human activities
Scientists in this section have said that they do not agree that most of the warming is due to human activities including (but not limited to) greenhouse gas emission.
Merlin notes for discussion: Explicitly in this category (i.e. have explicitly disagreed with the IPCC position)
William Kininmonth, meteorologist, former Australian delegate to World Meteorological Organization Commission for Climatology: "There has been a real climate change over the late nineteenth and twentieth centuries that can be attributed to natural phenomena. Natural variability of the climate system has been underestimated by IPCC and has, to now, dominated human influences."[4]
Merlin notes for discussion: Almost certainly in this category (i.e. I personally do not think synthesis is an issue)
William M. Gray, Professor Emeritus and head of The Tropical Meteorology Project, Department 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."[5] "I am of the opinion that [global warming] is one of the greatest hoaxes ever perpetrated on the American people."[6] "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."[7]Not sure what the last quote adds.
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."[8]
Tad Murty,
oceanographer; adjunct professor, Departments of Civil Engineering and Earth Sciences,
University of Ottawa: global warming "is the biggest scientific hoax being perpetrated on humanity. There is no global warming due to human anthropogenic activities. The atmosphere hasn’t changed much in 280 million years, and there have always been cycles of warming and cooling. The Cretaceous period was the warmest on earth. You could have grown tomatoes at the North Pole"[9]
Nicola Scafetta, research scientist in the physics department at
Duke University, wrote a booklet proposing a phenomenological theory of climate change based on the physical properties of the data. Scafetta describes his conclusions writing "At least 60% of the warming of the Earth observed since 1970 appears to be induced by natural cycles which are present in the solar system. A climatic stabilization or cooling until 2030–2040 is forecast by the phenomenological model."[10][11]
Roy Spencer, principal research scientist,
University of Alabama in Huntsville: "I predict that in the coming years, there will be a growing realization among the global warming research community that most of the climate change we have observed is natural, and that mankind’s role is relatively minor".[12]
Merlin notes for discussion: Arguably in this category
George V. Chilingar, Professor of
Civil and
Petroleum Engineering at the
University of Southern California: "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."[13]
Antonino Zichichi, emeritus professor of
nuclear physics at the
University of Bologna and president of the World Federation of Scientists : "models used by the Intergovernmental Panel on Climate Change (IPCC) are incoherent and invalid from a scientific point of view".[14] He has also said, "It is not possible to exclude that the observed phenomena may have natural causes. It may be that man has little or nothing to do with it"[15]
David Bellamy,
botanist, believes that climate change is part of the Earth's natural cycle and that such changes have been seen before. Says Bellamy, "The sun is getting old and it is getting warmer all the time but we do have cycles of sun spots and when those sun spots come the effect is to warm the Earth up and warm the atmosphere."[16]Merlin notes for discussion: Do we need this quote at all?
John Christy, professor of atmospheric science and director of the Earth System Science Center at the
University of Alabama in Huntsville, contributor to several
IPCC reports: "I'm sure the majority (but not all) of my IPCC colleagues cringe when I say this, but I see neither the developing catastrophe nor the smoking gun proving that human activity is to blame for most of the warming we see. Rather, I see a reliance on climate models (useful but never "proof") and the coincidence that changes in carbon dioxide and global temperatures have loose similarity over time."[17]
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."[18]Merlin notes for discussion: Concentrates on 20th Century rather than since 1950.
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.[19]Merlin notes for discussion: Concentrates on last century rather than since 1950.
Do not agree: most of the warming observed in the period 1950-2000 is attributable to human activities which cause emissions of greenhouse gases
Scientists in this section have specifically criticised the consensus position that most of the recent warming is due to human caused emissions of greenhouse gases.
Merlin notes for discussion: Explicitly in this category (i.e. have explicitly disagreed with the IPCC position)
Vincent R. Gray,
coal chemist, founder of the
New Zealand Climate Science Coalition: "The two main 'scientific' claims of the IPCC are the claim that 'the globe is warming' and 'Increases in carbon dioxide emissions are responsible'. Evidence for both of these claims is fatally flawed." (Oct 2007)[20]
Syun-Ichi Akasofu, retired professor of geophysics and Founding Director of the International Arctic Research Center of the University of Alaska Fairbanks: "[T]he method of study adopted by the International Panel of Climate Change (IPCC) is fundamentally flawed, resulting in a baseless conclusion: Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations. Contrary to this statement ..., there is so far no definitive evidence that 'most' of the present warming is due to the greenhouse effect. ... [The IPCC] should have recognized that the range of observed natural changes should not be ignored, and thus their conclusion should be very tentative. The term 'most' in their conclusion is baseless."[21]
Merlin notes for discussion: Almost certainly in this category (i.e. I personally do not think synthesis is an issue)
Richard Lindzen, Alfred P. Sloan Professor of Atmospheric Science at the
Massachusetts Institute of Technology 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."[22] "[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."[23][24]Merlin notes for discussion: Second statement seems to be arguing model is wrong because CO2 should have more effect than observed.
Khabibullo Abdusamatov,
mathematician and
astronomer at
Pulkovo Observatory of the
Russian Academy of Sciences: "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...Ascribing
'greenhouse' effect properties to the Earth's atmosphere is not scientifically substantiated...Heated greenhouse gases, which become lighter as a result of expansion, ascend to the atmosphere only to give the absorbed heat away."[25][26][27]
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."[29]
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."[30]
David Douglass,
solid-state physicist, professor, Department of Physics and Astronomy,
University of Rochester: "The observed pattern of warming, comparing surface and atmospheric temperature trends, does not show the characteristic fingerprint associated with greenhouse warming. The inescapable conclusion is that the human contribution is not significant and that observed increases in carbon dioxide and other greenhouse gases make only a negligible contribution to climate warming."[31]
William Happer, physicist specializing in
optics and
spectroscopy,
Princeton University: "all the evidence I see is that the current warming of the climate is just like past warmings. In fact, it's not as much as past warmings yet, and it probably has little to do with carbon dioxide, just like past warmings had little to do with carbon dioxide"[32]
Tim Patterson,[33]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?"[34][35]
Ian Plimer, Professor emeritus of
Mining Geology, The University of Adelaide: "We only have to have one volcano burping and we have changed the whole planetary climate... It looks as if carbon dioxide actually follows climate change rather than drives it".[36]
Tom Segalstad, head of the Geology Museum at the
University of Oslo: "The IPCC's temperature curve (the so-called 'hockey stick' curve) must be in error...human influence on the 'Greenhouse Effect' is minimal (maximum 4%). Anthropogenic CO2 amounts to 4% of the ~2% of the "Greenhouse Effect", hence an influence of less than 1 permil of the Earth's total natural 'Greenhouse Effect' (some 0.03 °C of the total ~33 °C)."[37]
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."[38][39] “It’s not automatically true that warming is bad, I happen to believe that warming is good, and so do many economists.”[40]Merlin notes for discussion: Last quote fits more into warming not necessarily negative.
Merlin notes for discussion: Arguably in this category
Don Easterbrook, emeritus professor of
geology,
Western Washington University: "global warming since 1900 could well have happened without any effect of CO2. If the cycles continue as in the past, the current warm cycle should end soon and global temperatures should cool slightly until about 2035"[41]
Do not agree: continued greenhouse gas emissions will cause temperatures to increase by 1.4 °C to 5.8 °C between 1990 and 2100
Merlin notes for discussion: Arguably in this category
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."[42]
*
Garth Paltridge, Visiting Fellow ANU and retired Chief Research Scientist, CSIRO Division of Atmospheric Research and retired Director of the Institute of the Antarctic Cooperative Research Centre."There are good and straightforward scientific reasons to believe that the burning of fossil fuel and consequent increase in atmospheric carbon dioxide will lead to an increase in the average temperature of the world above that which would otherwise be the case. Whether the increase will be large enough to be noticeable is still an unanswered question."[43]
Do not agree: impacts of global warming will be significantly negative, especially for larger values of warming
Merlin notes for discussion: Almost certainly in this category (i.e. I personally do not think synthesis is an issue)
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."[44]
Craig D. Idso, faculty researcher, Office of Climatology,
Arizona State University and founder of the
Center for the Study of Carbon Dioxide and Global Change: "the rising CO2 content of the air should boost global plant productivity dramatically, enabling humanity to increase food, fiber and timber production and thereby continue to feed, clothe, and provide shelter for their still-increasing numbers ... this atmospheric CO2-derived blessing is as sure as death and taxes." (May 2007)[45]
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." (2003)[46]
Merlin notes for discussion: Arguably in this category
Patrick Michaels, Senior Fellow at the
Cato Institute and retired
research professor of environmental science at the
University of Virginia: "scientists know quite precisely how much the planet will warm in the foreseeable future, a modest three-quarters of a degree (Celsius), plus or minus a mere quarter-degree ... a modest warming is a likely benefit... human warming will be strongest and most obvious in very cold and dry air, such as in Siberia and northwestern North America in the dead of winter." (October 16, 2003)[47]
Other arguments
Robert M. Carter, geologist, researcher at the Marine Geophysical Laboratory at
James Cook University in Australia: "the accepted global average temperature statistics used by the
Intergovernmental Panel on Climate Change show that no ground-based warming has occurred since 1998 ... there is every doubt whether any global warming at all is occurring at the moment (June 2007), let alone human-caused warming."[48]Merlin notes for discussion: Concentrates on warming (or lack of) since 2000
Willie Soon, astrophysicist,
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."[49] ''Merlin notes for discussion: So qualified it's difficult to say that it's a disagreement.
Philip Stott, professor emeritus of
biogeography at the
University of London: "...the myth is starting to implode. ... Serious new research at The
Max Planck Society has indicated that the sun is a far more significant factor..."[50]Merlin notes for discussion: Not specific.
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."[51]Merlin notes for discussion: Not specific.
Claude Allègre, geochemist, 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."[52]Merlin notes for discussion: Not specific.
Robert C. Balling, Jr., 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."[53]Merlin notes for discussion: Not specific.
Petr Chylek, Space and Remote Sensing Sciences researcher,
Los Alamos National Laboratory: "carbon dioxide should not be considered as a dominant force behind the current warming...how much of the [temperature] increase can be ascribed to CO2, to changes in solar activity, or to the natural variability of climate is uncertain"[54]Merlin notes for discussion: Mentions CO2, but too vague to fit easily into any of the categories.
Ross McKitrick, Assistant Professor in the Department of Economics at the University of Guelph, Ontario. His research found a strong correlation between surface temperature data and a nation's gross domestic product. A regression analysis revealed that a state's GDP explained about half of the warming over the observed period.[55] Mckitrick has remarked, "I have been probing the arguments for global warming for well over a decade. In collaboration with a lot of excellent coauthors I have consistently found that when the layers get peeled back, what lies at the core is either flawed, misleading or simply non-existent. ... I get exasperated with fellow academics, and others who ought to know better, who pile on to the supposed global warming consensus without bothering to investigate any of the glaring scientific discrepancies and procedural flaws."[56]Merlin notes for discussion: Not specific.
Surface temperatures measured by thermometers and lower atmospheric temperature trends inferred from satellites (red:
UAH; green:
RSS)
Now deceased
The lists above only include living scientists. The following are deceased.
Merlin notes for discussion: do we want to keep this section at all, if article is supposed to be about current views?
August H. "Augie" Auer Jr. (1940–2007) believed that the cause of global warming was unknown. Retired
New Zealand MetService Meteorologist, past professor of atmospheric science at the University of Wyoming, in 2006 he said: "So if you multiply the total contribution 3.6 by the man-made portion of it, 3.2, you find out that the anthropogenic contribution of CO2 to the global greenhouse effect is 0.117 percent, roughly 0.12 percent, that's like 12c in $100." "'It's miniscule ... it's nothing,'".[57]
Reid Bryson (1920–2008) believed global warming was primarily caused by natural processes.
Emeritus Professor of Atmospheric and Oceanic Sciences,
University of Wisconsin-Madison, in 2007 he said: "It’s absurd. Of course it’s going up. It has gone up since the early 1800s, before the Industrial Revolution, because we’re coming out of the
Little Ice Age, not because we’re putting more carbon dioxide into the air."[58]
Marcel Leroux (1938–2008) believed global warming was primarily caused by natural processes. former Professor of Climatology,
Université Jean Moulin, in 2005 he said: "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."[59]
Frederick Seitz (1911–2008) believed global warming was primarily caused by natural processes. Former
solid-state physicist, former president of the
National Academy of Sciences, in 2001 he said: "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."[60]
This article lists living and deceased scientists who have made statements that conflict with the mainstream assessment of global warming as summarized by the
Intergovernmental Panel on Climate Change and endorsed by other scientific bodies.
If greenhouse gas emissions continue the warming will also continue, with temperatures projected to increase by 1.4 °C to 5.8 °C between 1990 and 2100. Accompanying this temperature increase will be increases in some types of extreme weather and a projected
sea level rise of 9 cm to 88 cm, excluding "uncertainty relating to ice dynamical changes in the West Antarctic ice sheet". On balance the impacts of global warming will be significantly negative, especially for larger values of warming.[3]
This article is an attempt to list scientists who have made statements in disagreement with one or more of the principal conclusions of the Third (or Fourth) Assessment Report of the IPCC. Inclusion is based on the following specific criteria:
For the purposes of this list, qualification as a scientist is reached by publication of at least one peer-reviewed article in their lifetime in a broadly construed area of "natural sciences". The article need not have been written in recent years nor be in a field relevant to climate.
Attributable statements of disagreement in any venue in the individual's own words (not merely inclusion on petitions, surveys, or lists).
Scientists are listed with a recent quote which is representative of their views on climate change. The quote does not necessarily give details of all the nuances of their views on climate change. More detail can usually be found in the main article for that scientist.
Do not agree: global average surface temperature has risen 0.6 ± 0.2 °C since the late 19th century
There are currently no scientists listed in this category.
Do not agree: global average surface temperature has risen 0.17 °C per decade in the period 1970-2000
There are currently no scientists listed in this category.
Do not agree: most of the warming observed in the period 1950-2000 is attributable to human activities
Scientists in this section have said that they do not agree that most of the warming is due to human activities including (but not limited to) greenhouse gas emission.
Merlin notes for discussion: Explicitly in this category (i.e. have explicitly disagreed with the IPCC position)
William Kininmonth, meteorologist, former Australian delegate to World Meteorological Organization Commission for Climatology: "There has been a real climate change over the late nineteenth and twentieth centuries that can be attributed to natural phenomena. Natural variability of the climate system has been underestimated by IPCC and has, to now, dominated human influences."[4]
Merlin notes for discussion: Almost certainly in this category (i.e. I personally do not think synthesis is an issue)
William M. Gray, Professor Emeritus and head of The Tropical Meteorology Project, Department 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."[5] "I am of the opinion that [global warming] is one of the greatest hoaxes ever perpetrated on the American people."[6] "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."[7]Not sure what the last quote adds.
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."[8]
Tad Murty,
oceanographer; adjunct professor, Departments of Civil Engineering and Earth Sciences,
University of Ottawa: global warming "is the biggest scientific hoax being perpetrated on humanity. There is no global warming due to human anthropogenic activities. The atmosphere hasn’t changed much in 280 million years, and there have always been cycles of warming and cooling. The Cretaceous period was the warmest on earth. You could have grown tomatoes at the North Pole"[9]
Nicola Scafetta, research scientist in the physics department at
Duke University, wrote a booklet proposing a phenomenological theory of climate change based on the physical properties of the data. Scafetta describes his conclusions writing "At least 60% of the warming of the Earth observed since 1970 appears to be induced by natural cycles which are present in the solar system. A climatic stabilization or cooling until 2030–2040 is forecast by the phenomenological model."[10][11]
Roy Spencer, principal research scientist,
University of Alabama in Huntsville: "I predict that in the coming years, there will be a growing realization among the global warming research community that most of the climate change we have observed is natural, and that mankind’s role is relatively minor".[12]
Merlin notes for discussion: Arguably in this category
George V. Chilingar, Professor of
Civil and
Petroleum Engineering at the
University of Southern California: "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."[13]
Antonino Zichichi, emeritus professor of
nuclear physics at the
University of Bologna and president of the World Federation of Scientists : "models used by the Intergovernmental Panel on Climate Change (IPCC) are incoherent and invalid from a scientific point of view".[14] He has also said, "It is not possible to exclude that the observed phenomena may have natural causes. It may be that man has little or nothing to do with it"[15]
David Bellamy,
botanist, believes that climate change is part of the Earth's natural cycle and that such changes have been seen before. Says Bellamy, "The sun is getting old and it is getting warmer all the time but we do have cycles of sun spots and when those sun spots come the effect is to warm the Earth up and warm the atmosphere."[16]Merlin notes for discussion: Do we need this quote at all?
John Christy, professor of atmospheric science and director of the Earth System Science Center at the
University of Alabama in Huntsville, contributor to several
IPCC reports: "I'm sure the majority (but not all) of my IPCC colleagues cringe when I say this, but I see neither the developing catastrophe nor the smoking gun proving that human activity is to blame for most of the warming we see. Rather, I see a reliance on climate models (useful but never "proof") and the coincidence that changes in carbon dioxide and global temperatures have loose similarity over time."[17]
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."[18]Merlin notes for discussion: Concentrates on 20th Century rather than since 1950.
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.[19]Merlin notes for discussion: Concentrates on last century rather than since 1950.
Do not agree: most of the warming observed in the period 1950-2000 is attributable to human activities which cause emissions of greenhouse gases
Scientists in this section have specifically criticised the consensus position that most of the recent warming is due to human caused emissions of greenhouse gases.
Merlin notes for discussion: Explicitly in this category (i.e. have explicitly disagreed with the IPCC position)
Vincent R. Gray,
coal chemist, founder of the
New Zealand Climate Science Coalition: "The two main 'scientific' claims of the IPCC are the claim that 'the globe is warming' and 'Increases in carbon dioxide emissions are responsible'. Evidence for both of these claims is fatally flawed." (Oct 2007)[20]
Syun-Ichi Akasofu, retired professor of geophysics and Founding Director of the International Arctic Research Center of the University of Alaska Fairbanks: "[T]he method of study adopted by the International Panel of Climate Change (IPCC) is fundamentally flawed, resulting in a baseless conclusion: Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations. Contrary to this statement ..., there is so far no definitive evidence that 'most' of the present warming is due to the greenhouse effect. ... [The IPCC] should have recognized that the range of observed natural changes should not be ignored, and thus their conclusion should be very tentative. The term 'most' in their conclusion is baseless."[21]
Merlin notes for discussion: Almost certainly in this category (i.e. I personally do not think synthesis is an issue)
Richard Lindzen, Alfred P. Sloan Professor of Atmospheric Science at the
Massachusetts Institute of Technology 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."[22] "[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."[23][24]Merlin notes for discussion: Second statement seems to be arguing model is wrong because CO2 should have more effect than observed.
Khabibullo Abdusamatov,
mathematician and
astronomer at
Pulkovo Observatory of the
Russian Academy of Sciences: "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...Ascribing
'greenhouse' effect properties to the Earth's atmosphere is not scientifically substantiated...Heated greenhouse gases, which become lighter as a result of expansion, ascend to the atmosphere only to give the absorbed heat away."[25][26][27]
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."[29]
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."[30]
David Douglass,
solid-state physicist, professor, Department of Physics and Astronomy,
University of Rochester: "The observed pattern of warming, comparing surface and atmospheric temperature trends, does not show the characteristic fingerprint associated with greenhouse warming. The inescapable conclusion is that the human contribution is not significant and that observed increases in carbon dioxide and other greenhouse gases make only a negligible contribution to climate warming."[31]
William Happer, physicist specializing in
optics and
spectroscopy,
Princeton University: "all the evidence I see is that the current warming of the climate is just like past warmings. In fact, it's not as much as past warmings yet, and it probably has little to do with carbon dioxide, just like past warmings had little to do with carbon dioxide"[32]
Tim Patterson,[33]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?"[34][35]
Ian Plimer, Professor emeritus of
Mining Geology, The University of Adelaide: "We only have to have one volcano burping and we have changed the whole planetary climate... It looks as if carbon dioxide actually follows climate change rather than drives it".[36]
Tom Segalstad, head of the Geology Museum at the
University of Oslo: "The IPCC's temperature curve (the so-called 'hockey stick' curve) must be in error...human influence on the 'Greenhouse Effect' is minimal (maximum 4%). Anthropogenic CO2 amounts to 4% of the ~2% of the "Greenhouse Effect", hence an influence of less than 1 permil of the Earth's total natural 'Greenhouse Effect' (some 0.03 °C of the total ~33 °C)."[37]
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."[38][39] “It’s not automatically true that warming is bad, I happen to believe that warming is good, and so do many economists.”[40]Merlin notes for discussion: Last quote fits more into warming not necessarily negative.
Merlin notes for discussion: Arguably in this category
Don Easterbrook, emeritus professor of
geology,
Western Washington University: "global warming since 1900 could well have happened without any effect of CO2. If the cycles continue as in the past, the current warm cycle should end soon and global temperatures should cool slightly until about 2035"[41]
Do not agree: continued greenhouse gas emissions will cause temperatures to increase by 1.4 °C to 5.8 °C between 1990 and 2100
Merlin notes for discussion: Arguably in this category
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."[42]
*
Garth Paltridge, Visiting Fellow ANU and retired Chief Research Scientist, CSIRO Division of Atmospheric Research and retired Director of the Institute of the Antarctic Cooperative Research Centre."There are good and straightforward scientific reasons to believe that the burning of fossil fuel and consequent increase in atmospheric carbon dioxide will lead to an increase in the average temperature of the world above that which would otherwise be the case. Whether the increase will be large enough to be noticeable is still an unanswered question."[43]
Do not agree: impacts of global warming will be significantly negative, especially for larger values of warming
Merlin notes for discussion: Almost certainly in this category (i.e. I personally do not think synthesis is an issue)
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."[44]
Craig D. Idso, faculty researcher, Office of Climatology,
Arizona State University and founder of the
Center for the Study of Carbon Dioxide and Global Change: "the rising CO2 content of the air should boost global plant productivity dramatically, enabling humanity to increase food, fiber and timber production and thereby continue to feed, clothe, and provide shelter for their still-increasing numbers ... this atmospheric CO2-derived blessing is as sure as death and taxes." (May 2007)[45]
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." (2003)[46]
Merlin notes for discussion: Arguably in this category
Patrick Michaels, Senior Fellow at the
Cato Institute and retired
research professor of environmental science at the
University of Virginia: "scientists know quite precisely how much the planet will warm in the foreseeable future, a modest three-quarters of a degree (Celsius), plus or minus a mere quarter-degree ... a modest warming is a likely benefit... human warming will be strongest and most obvious in very cold and dry air, such as in Siberia and northwestern North America in the dead of winter." (October 16, 2003)[47]
Other arguments
Robert M. Carter, geologist, researcher at the Marine Geophysical Laboratory at
James Cook University in Australia: "the accepted global average temperature statistics used by the
Intergovernmental Panel on Climate Change show that no ground-based warming has occurred since 1998 ... there is every doubt whether any global warming at all is occurring at the moment (June 2007), let alone human-caused warming."[48]Merlin notes for discussion: Concentrates on warming (or lack of) since 2000
Willie Soon, astrophysicist,
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."[49] ''Merlin notes for discussion: So qualified it's difficult to say that it's a disagreement.
Philip Stott, professor emeritus of
biogeography at the
University of London: "...the myth is starting to implode. ... Serious new research at The
Max Planck Society has indicated that the sun is a far more significant factor..."[50]Merlin notes for discussion: Not specific.
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."[51]Merlin notes for discussion: Not specific.
Claude Allègre, geochemist, 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."[52]Merlin notes for discussion: Not specific.
Robert C. Balling, Jr., 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."[53]Merlin notes for discussion: Not specific.
Petr Chylek, Space and Remote Sensing Sciences researcher,
Los Alamos National Laboratory: "carbon dioxide should not be considered as a dominant force behind the current warming...how much of the [temperature] increase can be ascribed to CO2, to changes in solar activity, or to the natural variability of climate is uncertain"[54]Merlin notes for discussion: Mentions CO2, but too vague to fit easily into any of the categories.
Ross McKitrick, Assistant Professor in the Department of Economics at the University of Guelph, Ontario. His research found a strong correlation between surface temperature data and a nation's gross domestic product. A regression analysis revealed that a state's GDP explained about half of the warming over the observed period.[55] Mckitrick has remarked, "I have been probing the arguments for global warming for well over a decade. In collaboration with a lot of excellent coauthors I have consistently found that when the layers get peeled back, what lies at the core is either flawed, misleading or simply non-existent. ... I get exasperated with fellow academics, and others who ought to know better, who pile on to the supposed global warming consensus without bothering to investigate any of the glaring scientific discrepancies and procedural flaws."[56]Merlin notes for discussion: Not specific.
Surface temperatures measured by thermometers and lower atmospheric temperature trends inferred from satellites (red:
UAH; green:
RSS)
Now deceased
The lists above only include living scientists. The following are deceased.
Merlin notes for discussion: do we want to keep this section at all, if article is supposed to be about current views?
August H. "Augie" Auer Jr. (1940–2007) believed that the cause of global warming was unknown. Retired
New Zealand MetService Meteorologist, past professor of atmospheric science at the University of Wyoming, in 2006 he said: "So if you multiply the total contribution 3.6 by the man-made portion of it, 3.2, you find out that the anthropogenic contribution of CO2 to the global greenhouse effect is 0.117 percent, roughly 0.12 percent, that's like 12c in $100." "'It's miniscule ... it's nothing,'".[57]
Reid Bryson (1920–2008) believed global warming was primarily caused by natural processes.
Emeritus Professor of Atmospheric and Oceanic Sciences,
University of Wisconsin-Madison, in 2007 he said: "It’s absurd. Of course it’s going up. It has gone up since the early 1800s, before the Industrial Revolution, because we’re coming out of the
Little Ice Age, not because we’re putting more carbon dioxide into the air."[58]
Marcel Leroux (1938–2008) believed global warming was primarily caused by natural processes. former Professor of Climatology,
Université Jean Moulin, in 2005 he said: "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."[59]
Frederick Seitz (1911–2008) believed global warming was primarily caused by natural processes. Former
solid-state physicist, former president of the
National Academy of Sciences, in 2001 he said: "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."[60]