Lindzen in Newsweek

I wanted to write about this days ago, but I procrastinated… The story: Lindzen asked on Newsweek: Why So Gloomy?

The most extensive rebuttal I have seen so far is at Doug’s Darkworld who asked a friend who gave a long answer, taking it apart point by point. Another one is at reasic. And of course another one at the absolutely essential resource, realclimate.

Surprising is Lindzen’s blatant dishonesty. He seriously compares weather forecasts with climate models. He knows that there is a difference, that weather is not climate. Weather is chaotic, but a trend in climate is not. Every year as we approach summer it gets reliably warmer, but that does not mean that every day in spring is warmer than the previous one. We cannot predict the weather in two or three weeks, but we can be pretty sure it will be much warmer on average in a few months.

Another dishonesty is this:

Indeed, one overlooked mystery is why temperatures are not already higher. Various models predict that a doubling of CO2 in the atmosphere will raise the world’s average temperature by as little as 1.5 degrees Celsius or as much as 4.5 degrees. The important thing about doubled CO2 (or any other greenhouse gas) is its “forcing”—its contribution to warming. At present, the greenhouse forcing is already about three-quarters of what one would get from a doubling of CO2.

A simple calculation shows that this is wrong: the preindustrial level is 280 ppm, we currently have 380 ppm. So a doubling would be 560 ppm. The forcing is logarithmic to the concentration of the greenhouse gases, but ln(380/280)/ln(2) gives 44%. Read more about that at this post by James Annan at the globalchange google group. Not to mention that the temperature is not immediate. There will be a lag as the oceans heat up: even if the the greenhouse gas concentration suddenly froze at the current value, the earth would still heat up until it stabilizes. Those are things Lindzen knows.

Oh, and if you want to know more about Lindzen, just do a search for ‘Lindzen’ on realclimate.org.

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1 Comment

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One response to “Lindzen in Newsweek

  1. reasic

    Good post. I’ve seen Lubos Motl trot out that same argument about how we’ve already seen most of the warming we’d expect from doubling of CO2. I’ll have to ask him to explain that calculation for me. 😛