Mr. Lindzen, a professor on meteorology at the MIT and once a member of the National Academy of Sciences panel on climate change has written two articles denying that the scientific community settled the case on climate change as being manmade:
The Press Gets It Wrong
Our report doesn't support the Kyoto treaty.
by RICHARD S. LINDZEN
Monday, June 11, 2001 12:01 A.M. EDT
Last week the National Academy of Sciences released a report on climate change, prepared in response to a request from the White House, that was depicted in the press as an implicit endorsement of the Kyoto Protocol. CNN's Michelle Mitchell was typical of the coverage when she declared that the report represented "a unanimous decision that global warming is real, is getting worse, and is due to man. There is no wiggle room."
As one of 11 scientists who prepared the report, I can state that this is simply untrue. For starters, the NAS never asks that all participants agree to all elements of a report, but rather that the report represent the span of views. This the full report did, making clear that there is no consensus, unanimous or otherwise, about long-term climate trends and what causes them.
As usual, far too much public attention was paid to the hastily prepared summary rather than to the body of the report. The summary began with a zinger--that greenhouse gases are accumulating in Earth's atmosphere as a result of human activities, causing surface air temperatures and subsurface ocean temperatures to rise, etc., before following with the necessary qualifications. For example, the full text noted that 20 years was too short a period for estimating long-term trends, but the summary forgot to mention this.
Our primary conclusion was that despite some knowledge and agreement, the science is by no means settled. We are quite confident (1) that global mean temperature is about 0.5 degrees Celsius higher than it was a century ago; (2) that atmospheric levels of carbon dioxide have risen over the past two centuries; and (3) that carbon dioxide 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 carbon dioxide or to forecast what the climate will be in the future. That is to say, contrary to media impressions, agreement with the three basic statements tells us almost nothing relevant to policy discussions.
One reason for this uncertainty is that, as the report states, the climate is always changing; change is the norm. Two centuries ago, much of the Northern Hemisphere was emerging from a little ice age. A millennium ago, during the Middle Ages, the same region was in a warm period. Thirty years ago, we were concerned with global cooling.
Distinguishing the small recent changes in global mean temperature from the natural variability, which is unknown, is not a trivial task. All attempts so far make the assumption that existing computer climate models simulate natural variability, but I doubt that anyone really believes this assumption.
We simply do not know what relation, if any, exists between global climate changes and water vapor, clouds, storms, hurricanes, and other factors, including regional climate changes, which are generally much larger than global changes and not correlated with them. Nor do we know how to predict changes in greenhouse gases. This is because we cannot forecast economic and technological change over the next century, and also because there are many man-made substances whose properties and levels are not well known, but which could be comparable in importance to carbon dioxide.
What we do is know that a doubling of carbon dioxide by itself would produce only a modest temperature increase of one degree Celsius. Larger projected increases depend on "amplification" of the carbon dioxide by more important, but poorly modeled, greenhouse gases, clouds and water vapor.
The press has frequently tied the existence of climate change to a need for Kyoto. The NAS panel did not address this question. My own view, consistent with the panel's work, is that the Kyoto Protocol would not result in a substantial reduction in global warming. Given the difficulties in significantly limiting levels of atmospheric carbon dioxide, a more effective policy might well focus on other greenhouse substances whose potential for reducing global warming in a short time may be greater.
The panel was finally asked to evaluate the work of the United Nations' Intergovernmental Panel on Climate Change, focusing on the Summary for Policymakers, the only part ever read or quoted. The Summary for Policymakers, which is seen as endorsing Kyoto, is commonly presented as the consensus of thousands of the world's foremost climate scientists. Within the confines of professional courtesy, the NAS panel essentially concluded that the IPCC's Summary for Policymakers does not provide suitable guidance for the U.S. government.
The full IPCC report is an admirable description of research activities in climate science, but it is not specifically directed at policy. The Summary for Policymakers is, but it is also a very different document. It represents a consensus of government representatives (many of whom are also their nations' Kyoto representatives), rather than of scientists. The resulting document has a strong tendency to disguise uncertainty, and conjures up some scary scenarios for which there is no evidence.
Science, in the public arena, is commonly used as a source of authority with which to bludgeon political opponents and propagandize uninformed citizens. This is what has been done with both the reports of the IPCC and the NAS. It is a reprehensible practice that corrodes our ability to make rational decisions. A fairer view of the science will show that there is still a vast amount of uncertainty--far more than advocates of Kyoto would like to acknowledge--and that the NAS report has hardly ended the debate. Nor was it meant to.
Mr. Lindzen, a professor of meteorology at MIT, was a member of the National Academy of Sciences panel on climate change.
There is no ‘consensus’ on global warming
SAN FRANCISCO (Map, News) - By Richard S. Lindzen
According to Al Gore’s new film “An Inconvenient Truth,” we’re in for “a planetary emergency”: melting ice sheets, huge increases in sea levels, more and stronger hurricanes and invasions of tropical disease, among other cataclysms — unless we change the way we live now.
Bill Clinton has become the latest evangelist for Gore’s gospel, proclaiming that current weather events show that he and Gore were right about global warming, and we are all suffering the consequences of President Bush’s obtuseness on the matter. And why not? Gore assures us that “the debate in the scientific community is over.”
That statement, which Gore made in an interview with George Stephanopoulos on ABC, ought to have been followed by an asterisk. What exactly is this debate that Gore is referring to? Is there really a scientific community that is debating all these issues and then somehow agreeing in unison? Far from such a thing being over, it has never been clear to me what this “debate” actually is in the first place.
The media rarely help, of course. When Newsweek featured global warming in a 1988 issue, it was claimed that all scientists agreed. Periodically thereafter it was revealed that although there had been lingering doubts beforehand, now all scientists did indeed agree. Even Gore qualified his statement on ABC only a few minutes after he made it.
So, presumably, not all scientists belong to the “consensus.” Yet their research is forced, whether the evidence supports it or not, into Gore’s preferred global-warming template — namely, shrill alarmism. To believe it requires that one ignore the truly inconvenient facts.
To take the issue of rising sea levels, these include: that the Arctic was as warm or warmer in 1940; that icebergs have been known since time immemorial; that the evidence so far suggests that the Greenland ice sheet is actually growing on average. A likely result of all this is increased pressure pushing ice off the coastal perimeter of that island land, which is depicted so ominously in Gore’s movie.
In the absence of factual context, these images are perhaps dire or alarming. They are less so otherwise. Alpine glaciers have been retreating since the early 19th century, and were advancing for several centuries before that. Since about 1970, many of the glaciers have stopped retreating and some are now advancing again. And, frankly, we don’t know why.
The other elements of the global-warming scare scenario are predicated on similar oversights. Malaria, claimed as a byproduct of warming, was once common in Michigan and Siberia and remains common in Siberia — mosquitoes don’t require tropical warmth.
Hurricanes, too, vary on multidecadal time scales; sea-surface temperature is likely to be an important factor. This temperature, itself, varies on multidecadal time scales. Even among those arguing, there is general agreement that we can’t attribute any particular hurricane to global warming.
A general characteristic of Gore’s approach is to assiduously ignore the fact that the earth and its climate are dynamic; they are always changing even without any external forcing. To treat all change as something to fear is bad enough; to do so in order to exploit that fear is much worse. Regardless, these items are clearly not issues over which debate is ended — at least not in terms of the actual science.
A clearer claim as to what debate has ended is provided by the environmental journalist Gregg Easterbrook. He concludes that the scientific community now agrees that significant warming is occurring, and that there is clear evidence of human influences on the climate system.
This is still a most peculiar claim. At some level, it has never been widely contested. Most of the climate community has agreed since 1988 that global mean temperatures have increased on the order of one degree Fahrenheit over the past century, having risen significantly from about 1919 to 1940, decreased between 1940 and the early ’70s, increased again until the ’90s, and remaining essentially flat since 1998.
There is also little disagreement that levels of carbon dioxide in the atmosphere have risen from about 280 ppmv (parts per million by volume) in the 19th century to about 387 ppmv today. Finally, there has been no question whatsoever that carbon dioxide 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 carbon dioxide should have led to somewhat more warming than has been observed.
The models imply that greenhouse warming should impact atmospheric temperatures more than surface temperatures, and yet satellite data showed no warming in the atmosphere since 1979. The report showed that selective corrections to the atmospheric data could lead to some warming, thus reducing the conflict between observations and models descriptions of what greenhouse warming should look like. That, to me, means the case is still very much open.
So what, then, is one to make of this alleged debate? I would suggest at least three points.
First, nonscientists generally do not want to bother with understanding the science. Claims of consensus relieve policy types, environmental advocates and politicians of any need to do so. Such claims also serve to intimidate the public and even scientists — especially those outside the area of climate dynamics.
Secondly, given that the question of human attribution largely cannot be resolved, its use in promoting visions of disaster constitutes nothing so much as a bait-and-switch scam. That is an inauspicious beginning to what Gore claims is not a political issue but a “moral” crusade.
Lastly, there is a clear attempt to establish truth not by scientific methods but by perpetual repetition. An earlier attempt at this was accompanied by tragedy. Perhaps Marx was right. This time around we may have farce — if we’re lucky.
Richard Lindzen is the Alfred P. Sloan Professor of Atmospheric Science at MIT. Reprinted from The Wall Street Journal © 2006 Dow Jones & Company. All rights reserved.