EARTH IN THE BALANCE
Don't Believe the Hype
Al Gore is wrong. There's no "consensus" on global warming.
BY RICHARD S. LINDZEN
Sunday, July 2, 2006 12:01 a.m.
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 Mr. Gore's gospel,
proclaiming that current weather events show that he and Mr. Gore were right
about global warming, and we are all suffering the consequences of President
Bush's obtuseness on the matter. And why not? Mr. Gore assures us that "the
debate in the scientific community is over."
That statement, which Mr. Gore made in an interview with George
Stephanopoulos on ABC, ought to have been followed by an asterisk. What
exactly is this debate that Mr. 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 Mr. Gore qualified his
statement on ABC only a few minutes after he made it, clarifying things in
an important way. When Mr. Stephanopoulos confronted Mr. Gore with the fact
that the best estimates of rising sea levels are far less dire than he
suggests in his movie, Mr. Gore defended his claims by noting that
scientists "don't have any models that give them a high level of confidence"
one way or the other and went on to claim--in his defense--that scientists
"don't know. . . . They just don't know."
So, presumably, those scientists do not belong to the "consensus." Yet their
research is forced, whether the evidence supports it or not, into Mr. 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 country, which is depicted so ominously in Mr.
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. However, questions
concerning the origin of the relevant sea-surface temperatures and the
nature of trends in hurricane intensity are being hotly argued within the
profession.
Even among those arguing, there is general agreement that we can't attribute
any particular hurricane to global warming. To be sure, there is one
exception, Greg Holland of the National Center for Atmospheric Research in
Boulder, Colo., who argues that it must be global warming because he can't
think of anything else. While arguments like these, based on lassitude, are
becoming rather common in climate assessments, such claims, given the
primitive state of weather and climate science, are hardly compelling.
A general characteristic of Mr. 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 parts per million by volume in the 19th
century to about 387 ppmv today. Finally, there has been no question
whatever 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,
assuming that the small observed increase was in fact due to increasing
carbon dioxide rather than a natural fluctuation in the climate system.
Although no cause for alarm rests on this issue, there has been an intense
effort to claim that the theoretically expected contribution from additional
carbon dioxide has actually been detected.
Given that we do not understand the natural internal variability of climate
change, this task is currently impossible. Nevertheless there has been a
persistent effort to suggest otherwise, and with surprising impact. Thus,
although the conflicted state of the affair was accurately presented in the
1996 text of the Intergovernmental Panel on Climate Change, the infamous
"summary for policy makers" reported ambiguously that "The balance of
evidence suggests a discernible human influence on global climate." This
sufficed as the smoking gun for Kyoto.
The next IPCC report again described the problems surrounding what has
become known as the attribution issue: that is, to explain what mechanisms
are responsible for observed changes in climate. Some deployed the lassitude
argument--e.g., we can't think of an alternative--to support human
attribution. But the "summary for policy makers" claimed in a manner largely
unrelated to the actual text of the report that "In the light of new
evidence and taking into account the remaining uncertainties, most of the
observed warming over the last 50 years is likely to have been due to the
increase in greenhouse gas concentrations."
In a similar vein, the National Academy of Sciences issued a brief (15-page)
report responding to questions from the White House. It again enumerated the
difficulties with attribution, but again the report was preceded by a front
end that ambiguously claimed that "The changes observed over the last
several decades are likely mostly due to human activities, but we cannot
rule out that some significant part of these changes is also a reflection of
natural variability." This was sufficient for CNN's Michelle Mitchell to
presciently declare 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." Well, no.
More recently, a study in the journal Science by the social scientist Nancy
Oreskes claimed that a search of the ISI Web of Knowledge Database for the
years 1993 to 2003 under the key words "global climate change" produced 928
articles, all of whose abstracts supported what she referred to as the
consensus view. A British social scientist, Benny Peiser, checked her
procedure and found that only 913 of the 928 articles had abstracts at all,
and that only 13 of the remaining 913 explicitly endorsed the so-called
consensus view. Several actually opposed it.
Even more recently, the Climate Change Science Program, the Bush
administration's coordinating agency for global-warming research, declared
it had found "clear evidence of human influences on the climate system."
This, for Mr. Easterbrook, meant: "Case closed." What exactly was this
evidence? 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 Mr. 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.
Mr. Lindzen is the Alfred P. Sloan Professor of Atmospheric Science at MIT.
http://www.opinionjournal.com/extra/?id=110008597