When future generations come to look back on the alarm over global warming that seized the world towards the end of the 20th century, much will puzzle them as to how such a scare could have arisen. They will wonder why there was such a panic over a 0.4 per cent rise in global temperatures between 1975 and 1998, when similar rises between 1860 and 1880 and 1910 and 1940 had given no cause for concern. They will see these modest rises as just part of a general warming that began at the start of the 19th century, as the world emerged from the Little Ice Age, when the Earth had grown cooler for 400 years.
They will be struck by the extent to which this scare relied on the projections of computer models, which then proved to be hopelessly wrong when, in the years after 1998, their predicted rise in temperature came virtually to a halt.
But in particular they will be amazed by the almost religious reverence accorded to that strange body, the United Nations’ Intergovernmental Panel on Climate Change (IPCC), which by then will be recognised as having never really been a scientific body at all, but a political pressure group. It had been set up in the 1980s by a small band of politically persuasive scientists who had become fanatically committed to the belief that, because carbon dioxide levels were rising, global temperatures must inevitably follow; an assumption that the evidence would increasingly show was mistaken.
Five times between 1990 and 2014 the IPCC published three massive volumes of technical reports – another emerged last week – and each time we saw the same pattern. Each was supposedly based on thousands of scientific studies, many funded to find evidence to support the received view that man-made climate change was threatening the world with disaster – hurricanes, floods, droughts, melting ice, rising sea levels and the rest. But each time what caught the headlines was a brief “Summary for Policymakers”, carefully crafted by governments and a few committed scientists to hype up the scare by going much further than was justified by the thousands of pages in the technical reports themselves.
Each time it would emerge just how shamelessly these Summaries had distorted the actual evidence, picking out the scary bits, which themselves often turned out not to have been based on proper science at all. The most glaring example was the . . .