OPINION: ALL THOSE SCIENTISTS MAY STILL BE WRONG
The Daily Telegraph, 1 March 2007
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By Martin Livermore
On Sunday, Al Gore's film about climate change, An Inconvenient Truth,
won two Oscars. Today, the Royal Society starts a two-day event
showcasing the science of climate change according to the International
Panel on Climate Change (IPCC).
Both the film and conference are based on an understanding that the
science is settled. It isn't. But, in the meantime, the environmental
bandwagon rolls on, and no self-respecting politician wants to be left
without a seat.
Over the past century, the average global temperature rose by about
0.6C. This doesn't sound a lot, but represents changes noticeable to all
of us. At the same time, levels of carbon dioxide (CO2 ) in the
atmosphere have also risen, due, almost certainly, to our increasing use
of fossil fuels - coal, oil and gas. All else being equal, this would be
expected to lead to some moderate warming, as experienced.
The mainstream view, promulgated by the IPCC, is that this moderate
warming is enhanced by the extra water vapour that higher temperatures
put into the atmosphere. This positive feedback leads, in theory, to a
much greater temperature rise and has led to speculation about runaway
global warming.
But there are good reasons to believe that such a catastrophe is a
remote possibility, rather than a near certainty. The rise in
temperature has been far from smooth. The early decades of the 20th
century showed a distinct warming trend, peaking in the 1930s. However,
from the 1940s through to the early 1970s, temperatures fell -
sufficiently for commentators to raise the spectre of global cooling as
we slid into the next ice age. A sudden jump in the mid-1970s heralded
the return of a warming trend and led to the current concern about
global warming.
But peak temperatures were recorded in 1998; since then, we have had
eight years with no warming. In the meantime, CO2 levels have risen
inexorably.
Since we cannot experiment to test the effect of this on climate,
scientists rely on observation and, in parallel, produce mathematical
models of how the climate system operates. These models - fed with a
range of assumptions about how population and energy use may change -
are run on the world's most powerful supercomputers to give projections
for future climate changes. It is these on which tales of future
catastrophe are based.
But the climate over the past century has not behaved as simple models
predict. Scientists have tweaked the models to reproduce the stop/start
pattern, by adding in the effect of volcanic eruptions and man-made
sulphate aerosols. Because they can be made to simulate the actual
pattern of 20th-century temperature change, the assumption is that they
provide a good model of future changes.
What the modellers do not explain are documented changes to the climate
during recorded history. During the Roman Warm Period, England was a
significant wine producer, a thousand years later Greenland was settled
and farmed during the Medieval Warm Period, and harvests failed and ice
fairs were held on the frozen Thames in the Little Ice Age of the 17th
and 18th centuries. None of it was a result of man-made CO2 emissions.
The answer may lie in the ultimate source of warmth and life on Earth:
the sun. Solar activity varies in a cyclic way, with sunspots being an
obvious sign of changes. The more spots, the more active the sun. On a
simple level, we know that the Little Ice Age coincided with a very low
level of solar activity. We also know that the sun is currently in a
particularly active phase.
The IPCC's view is that these changes are too small to cause the climate
changes we have seen. But there is another factor, about which they are
equally dismissive: variations in the sun's magnetic field can have a
significant effect by influencing cloudiness.
It has been suggested that high energy cosmic rays, which arrive at the
Earth's surface all the time, could induce cloud formation. Recently,
experiments have shown that this can happen. And clouds, as we are all
aware, have a major effect on temperatures. The hypothesis is that the
more intense magnetic field of an active sun shields the Earth from some
of the rays.
So, if we have a more active sun, we should have fewer clouds and higher
temperatures. This is not fully tested, but seems as plausible a
mechanism for climate variation as the greenhouse effect. Knowledge of
solar cycles may be a better guide.
The scientific mainstream, however, refuses to concede that it could be
wrong. It insists we must act now to decarbonise our economy, whatever
the consequences. If the science were as certain as suggested, it would
have a point. But it isn't and, in the meantime, we are being forced
down a single policy direction that may be ineffectual and takes
resources away from the real and present problems in the world.
Increasing food security, providing access to clean water and basic
education, building defences against the floods that inevitably hit
low-lying regions: these are the sort of initiatives that have to take
second place to the drive to reduce carbon emissions.
In any case, there is little likelihood that a global carbon reduction
regime can be made to work. Most EU member states will not meet their
commitments under the Kyoto protocol. How likely is it, then, that China
and other expanding economies will compromise their growth to meet much
more demanding targets?
To shut down debate is unscientific. Science progresses by observation
and deduction, by setting up hypotheses and testing them. Allowing one
view to be pushed forward with no dissent sets a precedent that will
stifle innovative thinking. Whatever Al Gore may believe, there is an
even more inconvenient truth: he could be wrong.
* Martin Livermore is author of 'Climate Change: a Guide to the
Scientific Uncertainties', published by the Centre for Policy Studies
Copyright 2007, TDT