GDP inadequate as climate cost gauge - Stern

Nina Chestney in Reuters: The cost of global warming can no longer be quantified solely in terms of gross domestic product as the changes the world will experience and the resulting loss of life will be so immense, climate economist Nicholas Stern said on Wednesday. In 2006, Stern published a major report on the economics of climate change which said average global temperatures would rise by 2 to 3 degrees centigrade in the next 50 years and could reduce global consumption per head by up to 20 percent.

"That particular calculation had the one good model based on consumption and GDP but I would look at it now more broadly," Stern, who is chair of the Grantham Research Institute on Climate Change and the Environment at the London School of Economics, told Reuters in an interview.

"One simple measure of cost in terms of loss of GDP or consumption is a fairly narrow way of looking at things. It doesn't get at the full nature of the risk management question," he added, referring to the massive loss of life which would likely arise from billions of people being displaced due to floods and droughts if emissions are allowed to rise.

The latest climate science shows the planet has warmed by 0.8 degrees centigrade above last century but if left unmanaged the world could face temperatures of 4, 5 or 6 degrees higher this century, Stern said. The planet has not experienced such temperature rises for millions of years, he added.

...A 4, 5 or even 6 degree world is difficult to describe but many areas will turn into deserts, countries will submerge and the whole pattern of the north Indian monsoon might change which shapes the activity of hundreds of millions of people in the most densely populated parts of the world, he said. "Southern Europe looking like the Sahara desert, Bangladesh under water - these are the kinds of things that could happen."

Most climate models have underestimated the risks as they omit the timing and consequences of "tipping points", or thresholds beyond which a small additional rise in average temperature results in irreversible changes, Stern added...

A Burroughs adding machine from the 1890s, shot by trekphiler, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license