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,” Ive 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.

via Matt Ridley: Whatever Happened to Global Warming? – WSJ.

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