A sea-change on climate sensitivity at The Economist

People send me stuff, today it was this “editors picks” from John Micklethwait, editor of The Economist. After years of being pro-warming, I was shocked to see this headline as a “pick”. It seems a change in editorial position may be afoot.

The article is quite blunt, and quite interesting for its details, here is the introduction:

OVER the past 15 years air temperatures at the Earth’s surface have been flat while greenhouse-gas emissions have continued to soar. The world added roughly 100 billion tonnes of carbon to the atmosphere between 2000 and 2010. That is about a quarter of all the CO₂ put there by humanity since 1750. And yet, as James Hansen, the head of NASA’s Goddard Institute for Space Studies, observes, “the five-year mean global temperature has been flat for a decade.”

Temperatures fluctuate over short periods, but this lack of new warming is a surprise. Ed Hawkins, of the University of Reading, in Britain, points out that surface temperatures since 2005 are already at the low end of the range of projections derived from 20 climate models (see chart 1). If they remain flat, they will fall outside the models’ range within a few years.

The mismatch between rising greenhouse-gas emissions and not-rising temperatures is among the biggest puzzles in climate science just now. It does not mean global warming is a delusion. Flat though they are, temperatures in the first decade of the 21st century remain almost 1°C above their level in the first decade of the 20th. But the puzzle does need explaining.

The mismatch might mean that—for some unexplained reason—there has been a temporary lag between more carbon dioxide and higher temperatures in 2000-10. Or it might be that the 1990s, when temperatures were rising fast, was the anomalous period. Or, as an increasing body of research is suggesting, it may be that the climate is responding to higher concentrations of carbon dioxide in ways that had not been properly understood before. This possibility, if true, could have profound significance both for climate science and for environmental and social policy.

…

Clouds of uncertainty

This also means the case for saying the climate is less sensitive to CO₂ emissions than previously believed cannot rest on models alone. There must be other explanations—and, as it happens, there are: individual climatic influences and feedback loops that amplify (and sometimes moderate) climate change.

…

That last paragraph meshes very well with recent publications about lower climate sensitivity, which they reference.

Read the entire article here: http://www.economist.com/news/science-and-technology/21574461-climate-may-be-heating-up-less-response-greenhouse-gas-emissions

While we are on the subject of sensitivity, they mention the recent paper by Nic Lewis who writes:

It even cites a paper that I’ve recently had accepted for publication, and which I think will at least get a mention in AR5 WG1.

They also have an editorial which says:

All in all, I think this is tremendous progress. Kudos to The Economist for embracing this maxim:

When my information changes, I alter my conclusions. What do you do, sir?

– John Maynard Keynes

h/t to Nic Lewis and Dr. Roger Pielke Sr.