.... and my email to him:
I have derived a great deal of pleasure from your writings and broadcasts over many years but your broadcast this morning on Radio 4 filled me with dismay.
I’m afraid that your assessment of the climate science debate was profoundly mistaken – on a number of counts.
Don’t worry, I don’t intend to bombard you with the scientific evidence that counters the claims of the denialists (you can read this for yourself if you wish at sites such as http://www.newscientist.com/article/dn11462) but I do wish to explain why the climate change deniers really are on a par with Holocaust deniers.
First of all, most of the science is about what has already happened and what is happening now. Nobody (except the scientifically illiterate - I think here of “journalists” such as Melanie Phillips) disputes the figures for the amount of carbon in the atmosphere and the growth of those figures in response to the burning of fossil fuels. Nobody (except the scientifically illiterate) disputes the claim that CO2 in the atmosphere leads (ceteris paribus) to a “greenhouse effect”. This much is basic physics and chemistry.
Of course scientists also claim that there has been a long term increase in average global temperatures and here they are on slightly shakier ground. The written records only go back so far and many of the figures have to be inferred from all kinds of other disparate evidence. The accuracy of historical records and the validity of such inferences may be disputed (on perfectly reasonable scientific grounds). Nonetheless, there is a very very wide consensus amongst scientists that there has been a warming trend in average global temperatures since we began burning lots of fossil fuels.
The claims of many denialists that climate scientists are engaged in some kind of conspiracy to delude the rest of us are belied by the fact that those same scientists have reported a slight cooling trend in very recent years. Of course, the assumption is that this is a short term blip in an otherwise relentless upward trend…
…which brings me to my final point; and your most serious error:
None of the science described above is based on “modelling”. Computer modelling of the climate is designed to predict what might happen in the future. Of course, nobody knows for certain what will actually happen in the future. For example, the super-volcano under Yellowstone Park may blow and plunge us all into a decades long winter. But computer models can provide educated guesses as to what is most likely to happen given certain assumptions about continuing trends. There is far less scientific consensus here (especially when it comes to the details) but there is a very widespread scientific consensus that (assuming current trends do continue unabated) some pretty dreadful things are very likely to happen over the next couple of hundred years.
There are some who have genuine scientific concerns about things like the measurement of average sea temperatures and the rate of ice sheet melting and so on; but they are in a minority. Most of the “scientists” who tend to get quoted by journalists seeking to discredit the theory of global warming are scientists in the same sense that David Irving is an historian.