Gwynne Dwyer is clearly an educated man, but when it comes to science and its history, he is equally clearly propping up the saloon bar.
In his article on addressing climate change (Sunday 31st May), he suggests that we need to act now before the rise in global temperature becomes a significant problem.
The earth’s climate variations are subject to numerous “feedback loops”. It is a “toppling system”. For example, a one per cent rise in ocean temperature over ten years releases about three times more CO2 into the atmosphere than mankind puts in over that period (Google “Keeling Curves”) plus water vapour – the most effective greenhouse gas. This in turn raises the temperature another degree…and so on.
Over the past one million years this has happened about 40 times. These events are called “ice ages”, with intervening warming. What causes them without Man helping out? They are caused by the Malenkovitch Cycles – variations in the earth’s orbit. These only create a minor (1oC?) warming, but this kicks off a feedback loop.
It is quite likely that Man has tripped such an effect over the past century by releasing large quantities of CO2 into the atmosphere. However, the other side of the coin is that there is very little we can do about it. The forces involved are way beyond forces we can command.
But Mr Dwyer’s second point, global engineering, is potentially far more catastrophic than global warming. Quite apart from the fact that the science of geophysics is in its infancy, the history of science gives us a stark warning. Throughout the last four centuries of scientific advance, one common occurrence in every field is “unforeseen consequences”.
When Newton examined the spectrum of sunlight, he unexpectedly found a distortion in the image, leading to new optical theory. Moving on, when Priestley was studying burning elements the unexpected result was an increase in weight. In the nineteenth century, the attempt to measure the medium of light transmission unexpectedly yielded the result that it couldn’t be detected. Curie and radio-activity. Fleming and penicillin. Etc, etc…
These are all fascinating results in the laboratory – but we do not want unexpected results when the test-tube we are using is the earth’s atmosphere! Anything unexpected happening (which we may confidently expect) is likely to be disastrous. To toy like a child with the earth’s climate might well be our last folly.
Derek Smith, Oroklini