Monday, July 18, 2011

Being skeptical of the skeptics - Bob Carter edition

Adj Prof Bob Carter is one of Australia's most prominent climate "skeptics". Unlike most climate "skeptics" he is a scientist, although the number of scientific papers he has published on climate change are few to nonexistent).

A couple of months back Bob gave a talk to the Sydney Mining Club where he repeated many of his claims, including that the planet is not warming due to greenhouse gasses and that he doesn't think it is warming at all. Personally I'm skeptical of his claims and I'm not the only one, a statistician/ climate scientist who blogs under the name Tamino, decided to do what real skeptics do and test Bob's claims.

The result (which I highly recommended people read if you have time) is an incredible demolition of Carter's claims. Here's just one of them.

Bob takes the temperature record of the lower atmosphere as determined by satellites (which started in 1979) and claims it doesn't show warming. He then claims that temperature trend is for flat temperatures before and after 1998 with a jump in the middle. Here's the slide:

Scientifically this is bizarre, the correct way to check for warming is to calculate the trend over the entire series, but Bob doesn't like this idea (hint: it shows warming). But actually it gets worse because it turns out his red "trend lines" are not trend lines at all. He just made them up to show the answer he wanted, which was no change in temperature. How do we know? Because when Tamino calculated the change in temperature over this time period he got this.

In both cases the trend is up, ie: temperatures increased.

But I'm a skeptical person so I shouldn't just take Tamino's word. So I went and drew some trends too using the same data. It's easy, you can do it here.
I checked the temperature trend in the atmosphere since 1979 and the trend since 1999 (Carter's second red line) and lo and behold I found that Tamino was right and Carter's "trend" was fake.

What Carter has done wouldn't be acceptable for a first year university student, but Carter is suppose to be a scientist and this is just one of the errors in his presentation.
From all this I draw two conclusions.
1. Whatever credibility Carter once had in the climate debate, it's gone.
2. It is good, although time consuming, to be skeptical of both those you agree and disagree with. That way you know, as Whitey Ford said, "who's real and who's faking".

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