HTAG Guildford - All those scientists may still be wrong

Front Page >> Features >> Global Warming Information >> All those scientists may still be wrong

All those scientists may still be wrong

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 (IPPC). 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 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 feed back 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 1930's. However, from the 1940's through to the early 1970's, 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-1970's 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, carbon dioxide 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 carbon dioxide 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 hypotheses 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 decarbonize 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 my 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 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.

For further study read "Climate Change: a Guide to the Scientific Uncertainties" published by the Centre for Policy Studies

Martin Livermore -

Menu

Front Page