The pause and its coming of age
Sep 5, 2014
Bishop Hill in Climate: Surface, Matt Ridley

There should be a big coming of age party for the pause in the next month or so. On one measure it's now 17 years, 11 months old, so depending what temperatures do in the near future the pause should be heading for the local boozer for its first pint.

In fact on other measures the pause is already well into adulthood, as Matt Ridley reports in the Wall Street Journal.

Well, the pause has now lasted for 16, 19 or 26 years—depending on whether you choose the surface temperature record or one of two satellite records of the lower atmosphere. That’s according to a new statistical calculation by Ross McKitrick, a professor of economics at the University of Guelph in Canada.

It has been roughly two decades since there was a trend in temperature significantly different from zero. The burst of warming that preceded the millennium lasted about 20 years and was preceded by 30 years of slight cooling after 1940.

This has taken me by surprise. I was among those who thought the pause was a blip. As a “lukewarmer,” I’ve long thought that man-made carbon-dioxide emissions will raise global temperatures, but that this effect will not be amplified much by feedbacks from extra water vapor and clouds, so the world will probably be only a bit more than one degree Celsius warmer in 2100 than today. By contrast, the assumption built into the average climate model is that water-vapor feedback will treble the effect of carbon dioxide.

But now I worry that I am exaggerating, rather than underplaying, the likely warming.

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