What the UN Wont Tell You
By Ross McKitrick
Newsweek International
Jan. 12, 2007 issue - Last Friday, the Intergovernmental
Panel on Climate
Change, the United Nations group charged with assessing the
state of the
world's climate, unveiled the summary of its latest report.
The IPCC Web
site claims an impressive number of participants: 450 lead
authors, 800
contributors and 2,500 expert reviewers (of which I was
one). But it would
be a mistake to assume all these experts endorse everything
in summary,
including its bottom-line assessment: "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."
Many disagree with the conclusion itself or the claimed
level of certainty,
but the fact is, we were never asked. Most participants
worked only on small
portions of the report, handed in final materials last
summer and never
ventured an opinion on claims made in the summary.
Nor can readers check how well the summary reflects the
underlying science.
The report itself will not be distributed until May.
Although it was
officially "released" on Feb. 2, the IPCC is going
over the wording to make
sure it is consistent with the summary. This is a curious
and disconcerting
aspect of IPCC procedures: it needs a couple of months to
revise a detailed
report prepared by hundreds of scientists, to ensure it
agrees with a brief
summary drafted by a few dozen scientists and edited by
hundreds of
bureaucrats and politicians.
To be sure, the IPCC does an impressive job of mobilizing
experts to produce
a report it hopes will be of service to the world. No one
should trivialize
this achievement. But let's not make the error of allowing a
glossy summary
to trivialize the complexities and uncertainties in climate
change. After
all, if the issues were so simple, you wouldn't need 3,700
experts to write
the report. It is a paradox that some of the strongest
claims of unanimity
in science are made on a subject involving some of the
deepest intellectual
disagreements and uncertainties.
For instance, the study of climate begins with the movements
of fluids: the
oceans and atmosphere. The mathematics describing fluids in
motion were
derived by Claude-Louis Navier and George Gabriel Stokes
more than a century
ago, but no one has been able to put the equations in a form
that would be
useful for predicting many key climatic processes. The Clay
Institute of
Mathematics in Cambridge, Massachusetts, offers a $1 million
prize for
anyone who can solve the "Navier-Stokes problem,"
or even just prove that a
solution is possible.
In lieu of a solution, scientists use computer models to
approximate how the
countless processes affecting the climate might behave over
time. The IPCC
report explains many important limitations of these models:
the summary
ignores them. The report fails to achieve balance in other
places. For
instance, in its 2001 report, the IPCC effectively denied
the view that the
Earth's climate had cycled through warming and cooling for
10 centuries
prior to today's warming. The famous "hockey
stick" graph implied warming
began with industrialization. I am skeptical of this claim,
based on a lot
of research—including some high-level expert reviews last
year—that showed
the data did not support the IPCC claim. The 2007 report
admits problems in
this earlier view, but goes on to claim that climate is
likely the warmest
in 1300 years—precisely what the data don't support.
The IPCC also denies that its estimate of rising
temperatures, based on
weather data collected in ground-level stations around the
world, is
affected by warming biases due to land-use change,
urbanization and the
sudden closure of half the world's monitoring stations in
the early 1990s. I
am skeptical of their position, based on work I and others
have done showing
correlations between these influences and temperature
trends.
There are other examples. Numerous analyses of solar data
suggest the sun's
output has intensified since the 17th century, and its
indirect effect on
cloud formation may further amplify its influence on the
climate, implying
much of 20th-century climate change is natural. One recent
study, by
contrast, suggests almost no solar intensification has
occurred since the
17th century. That's the study you will read about most in
the IPCC report
summary.
The IPCC leaders have a point of view. Think of their report
as the case for
the prosecution. Maybe this time the district attorney is
right. Maybe not:
that is why we need to hear from the defense as well.
McKitrick is associate professor of economics at the
University of Guelph
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