According to a recent piece on the BBC website "The severity of global warming over the next century will be much worse than previously believed, a leading climate scientist has warned." In this case, Professor Chris Field has told the American National Academy of Sciences meeting that, since greenhouse gas emissions have been rising more rapidly than expected (a statement which in itself deserves to be questioned), the predicted 1.1 to 6.4 degree Celsius average temperature rise over the next century is likely to be a serious underestimate.
And Prof Fields is not alone in his predictions of catastrophe. James Lovelock, proposer of the Gaia theory and catastrophist-in-chief, no longer talks of global warming, but global heating. He believes mankind's malign influence has gone too far to be reversible, that investment in renewable energy generation is a waste of time (I wouldn't disagree with that) and that remnants of the human race will only survive in polar regions and a few favoured islands such as the UK and New Zealand.
The only problem is that the doom-mongering is all based on the unproven hypothesis that anthropogenic emissions of carbon dioxide are having a dominant effect on climate. However, in the past ten years, there has been no rise in average temperatures and no evidence (other than the output of flawed computer models) to suggest that mainstream climate science is right. It is equally plausible that the quiet period of solar activity which started recently (as shown by a dearth of sunspots) will be lead to a cooling of the climate, as has always been the case in the past. Adam Smith himself noted the increased price of wheat in times of low sunspot numbers.
Time will tell, but in the meantime expect more scary headlines based on selective use of evidence by scientists convinced their theory is right.
Guest author Martin Livermore is the Director of The Scientific Alliance