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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 Ján 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 Liège 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.
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