The Rational Optimist_ How Prosperity Evolves - Matt Ridley [153]
If, that is, the climate does not lurch into chaos.
Climate
In the mid-1970s it was briefly fashionable for journalists to write scare stories about the recent cooling of the globe, which was presented as undiluted bad news. Now it is fashionable for them to write scare stories about the recent warming of the globe, which is presented as undiluted bad news. Here are two quotes from the same magazine three decades apart. Can you tell which is about cooling and which about warming?
The weather is always capricious, but last year gave new meaning to the term. Floods, hurricanes, droughts – the only plague missing was frogs. The pattern of extremes fit scientists’ forecasts of what a ——world would be like.
Meteorologists disagree about the cause and extent of the ——trend, as well as over its specific impact on local weather conditions. But they are almost unanimous in the view that the trend will reduce agricultural productivity for the rest of the century ... The longer the planners delay, the more difficult will they find it to cope with climatic change once the results become grim reality.
The point I am making is not that one prediction proved wrong, but that the glass was half empty in both cases. Cooling and warming were both predicted to be disastrous, which implies that only the existing temperature is perfect. Yet climate has always varied; it is a special sort of narcissism to believe that only the recent climate is perfect. (The answer by the way is that the first one was a recent warning about warming; the second an old warning about cooling – both are from Newsweek.)
I could plunge into the scientific debate and try to persuade you and myself that the competitive clamour of alarm is as exaggerated as it proved to be on eugenics, acid rain, sperm counts and cancer – that the warming the globe faces in the next century is more likely to be mild than catastrophic; that the last three decades of relatively slow average temperature changes are more compatible with a low-sensitivity than a high-sensitivity model of greenhouse warming; that clouds may slow the warming as much as water vapour may amplify it; that the increase in methane has been (erratically) decelerating for twenty years; that there were warmer periods in earth’s history in medieval times and about 6,000 years ago yet no accelerations or ‘tipping points’ were reached; and that humanity and nature survived much faster warming lurches in climate during the ice ages than anything predicted for this century. There are respectable scientific arguments to support all these arguments – and in some cases respectable scientific ripostes to them, too. But this is not a book about the climate; it is about the human race and its capacity for change. Besides, even if the current alarm does prove exaggerated, there is now no doubt that the climate of this planet has been subject to natural lurches in the past, and that though luckily there has been no huge lurch for 8,200 years, there have been some civilisation-killing perturbations – as the ruins at both Angkor Wat and Chichen Itza probably testify. So if only hypothetically, it is worth asking whether civilisation could survive climate change at the rate assumed by the consensus of scientists who comprise the Intergovernmental Panel on Climate Change (IPCC) – that is, that the earth will warm during this century by around 3°C.
However, that is just a mid-range figure. In 2007 the IPCC used six ‘emissions scenarios’, ranging from a fossil-fuel-intensive, centennial global boom to something that sounds more like a sustainable, groovy fireside sing-along, to calculate how much temperature will increase during the century. The average temperature increases