I am just a little more inclined to believe that CO2
emissions might be the cause of the present warm period in the earth's
climate (though the earth is far from being uniformly warmer) than I was
the last time this subject came up on FW. However, even if the earth's
temperature rises a little, the cost of trying to negate this would be
gigantic compared with the costs of putting up with it, such as moving
populations from low lying areas.
A couple of years ago, many became quite hysterical over this --
particularly the EC Commissioners who saw this as a wonderful opportunity
to make themselves more important. Despite jaunts around the world, they
didn't succeed in convincing Russia, China or America which have 95% of
the world's leading meteorologists and oceanographers between them, so
the matter is relatively quiescent at the moment. Furthermore, it is now
widely agreed that many of the economic extrapolations used as arguments
for taxation in the original IPCC report were fallacious, and seriously
so, too.
Both Harry and I have counselled caution on this list until the
measurements of two recently launched environmental satellites are fully
collated and analysed. At the very least, they will fill some very large
holes in the existing data (so far, temperature readings from only about
one quarter of the land surface of the world and almost none from the
oceans) and, at best, can give definitive information on which sensible
political decisions can be much more reliably based -- if they need
to be.
For those who are still interested in the matter, the following article
by Prof Stott, professor emeritus of biogeography at London University,
will be of interim interest.
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YOU CAN'T CONTROL THE CLIMATE
Reducing carbon emission in the hope this will stop global warming is a
flawed idea. Better to react to climate change as it happens
Philip Stott
In Europe, the story of human-made global warming has become almost as
unassailable as the Genesis creation story in parts of the American Bible
Belt. It has morphed into a hegemonic myth, such that any scientific
research that challenges it is neither reported in the media nor
considered by politicians and policy makers. Whatever your opinion on the
mechanics and extent of global warming, this is a pity. Not only does
repressing critical science make for an ill-informed debate, it can also
result in policy decisions founded on uncertain scientific
conclusions.
Let me declare my position: I am a mildly left-wing global warming
sceptic. For me, the real questions have never been, "Is climate
changing?" or "Are humans influencing climate?"
Climate always changes, and humans affect climate in many ways, not just
through carbon dioxide emissions. I don't believe we will ever be able to
manage the climate in a predictable manner by trying to manipulate Just
one of the enormous number of natural and human factors
involved.
My position is reinforced by recent scientific research. Over the past
few weeks, a number of studies have emerged that cast doubt on the
significance of human-made global warming and the climate models on which
the dominant theory is largely based. But don't be surprised if you
haven't heard of them.
One of the most important investigates the link between climate change
and galactic cosmic rays (GSA Today, vol 13, p 4). Cosmic rays are
known to boost cloud formation -- and in turn reduce temperatures on
Earth -- by creating ions that cause water droplets to condense.
Geochemist Jan Veizer of the Ruhr University at Bochum, Germany, and the
University of Ottawa in Canada, and Nir Shaviv, an astrophysicist at the
Racah Institute of Physics at the Hebrew University of Jerusalem,
calculated temperature changes at the Earth's surface by studying oxygen
isotopes trapped in rocks formed by ancient marine fossils. They then
compared these with variations in cosmic-ray activity, determined by
looking at how cosmic rays have affected iron isotopes in
meteorites.
Their results suggest that temperature fluctuations over the past 550
million years are more likely to relate to cosmic-ray activity than to
CO2. Cosmic rays could account for as much as 75 per cent of climate
variations, they argue. By contrast, the researchers found no correlation
between temperature variation and the changing patterns of CO2 in the
atmosphere.
This research underlines the serious gaps in our knowledge of how CO2
behaves in the atmosphere. It is often taken as read by politicians, the
media and much of the scientific community that increased levels of the
gas lead directly to higher temperatures. Yet the mechanism is far from
understood. This was emphasised by Veizer in a paper in Nature in
2000 (vol 408, p 698), in which he and two colleagues from the University
of Liege in Belgium illustrated the serious mismatches between CO2 levels
and climate variability in the geological record.
Another study, published last month, highlights weaknesses in the
"general circulation models", the computer simulations of the
Earth's atmosphere that are among the chief tools of modern climate
research. In Progress in Physical Geography (vol 27, p 448),
Willie Soon and Sallie Baliunas of the Harvard-Smithsonian Center for
Astrophysics point out that a number of scientists have already called
for better models that more accurately reflect the extremely complicated
interactions between atmosphere, ocean, land and ice cover.
Improving them, they argue, will require long-term monitoring of several
key factors that affect the climate that are not yet sufficiently
understood by climate scientists. These include radiation, magnetised
plasma and energetic particles from the sun; the crucial properties of
clouds; and variations in the shape of the Earth, which has a significant
influence on atmospheric flow and climate.
Soon and Baliunas go on to stress that no general circulation model has
successfully simulated the observation that while temperatures at the
surface of the Earth have continued to rise, the lower atmosphere has not
warmed at all. Yet if CO2 plays the substantial role in climate change
the global warming lobby insists it does, this layer should be warming
faster than the surface air.
It seems clear, then, that our climate models are very limited, and that
we have a long way to go before the observations on which they are based
can be used to dictate policy. Though the "global warming myth"
has become immensely powerful, the science of climate change remains
deeply uncertain. I believe it is vital to acknowledge this uncertainty.
Our crucial mistake is in trying to manage the climate in the vain hope
that we can predict it. Instead, we should put our resources into
adapting economically and socially -- especially at a local and regional
level -- to whatever it throws at us. I am certain of only one thing: the
climate will surprise us.
New Scientist 18 September 2003
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