Climatology’s great dilemma

Climate science is, once again, on the horns of a very uncomfortable dilemma. Whatever the Intergovernmental Panel on Climate Change (IPCC) chooses to do in the next few weeks its decision looks set to explode in its face.

Crises are something of a feature of the IPCC. Since its First Assessment appeared back in 1990, each of the panel’s periodic pronouncements on the global climate has plunged it into controversy. In the Second Assessment of 1995, the report’s headline claim – that a ‘fingerprint’ of manmade global warming had been detected – caused uproar when it was discovered that it had been inserted into the text at the last moment. Loud allegations that the report had been doctored for political ends followed. Then, in 2001, the infamous, but scientifically peripheral Hockey Stick graph, with its claim that modern temperatures are unprecedented, was hyped by the Third Assessment as though it were conclusive evidence of a human influence on the climate.