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Interview with a link denier |
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Sept. 15 Story on "scientific" debunking of global warming connection.
Debunker Point 1. "First is the erroneous claim that hurricane intensity or frequency has risen significantly in recent decades in response to the warming trend seen in surface temperature."
Debunker claim: Hurricane intensity has gone down since the 1940's.
Reality: There was a down trend from 1940 till about 1985, then it turned up as predicted because of the North Atlantic Oscillation (see graph). The scientists making the global-warming-hurricane link point this out. They say the recent upturn appears to be too strong and corresponds to similar upturns in 5 other hurricane basins.
Debunker claim: "Reliable data ... since the 1940s indicate that the peak strength of the strongest hurricanes has not changed."
Reality: Same point is made by the other side.
Debunker claim: "the mean maximum intensity of all hurricanes has decreased."
Reality: I've seen their graph. They fit a straight line from 1940 on, and it slopes down. I tried it myself, and sure enough it did. Then I asked excel to fit a curve and it went down till about 1975 and then up, much like Dr. Emanuel's graph.
Debunker claim: "Recent history tells us that hurricanes are not becoming more frequent."
Reality: Both the Science and Nature articles emphasize this point and agree with it. Their point instead is that the percentage of category 4 and 5 storms is increasing in every hurricane basin but not the total number.
Debunker Point 2. It is "demonstrably false" that a future surface warming trend would lead to more frequent and stronger storms.
Debunker claim: "Computer simulations suggest that in a warmer world most of the warming would occur in the Polar Regions. Atmospheric circulation, which crucially affects storms, is driven primarily by the temperature difference, or gradient, between the tropics and the poles."
Reality: Undoubtedly there are such simulations, but I have not yet found them. The most prestigious set of simulations appears to be described on NOAA.gov and they say exactly the opposite.
The main contradiction in the debunker position is that they say the sharp rise in destructive hurricanes since 1995 is not from global warming but from the North Atlantic oscillation. That much is largely true, but this is what they know but conveniently "forget." The way that oscillation works is to warm and cool the tropical ocean and when it warms it, like now, we get much stronger hurricanes. Then they conclude that global warming, which would also warm those waters, wouldn't cause the same thing, because their computer models don't quite agree with what we are seeing. But what we are seeing is, in fact, caused by warmer waters, even the debunkers admit that.
The scientists writing in Science and Nature are taking very cautious scientific-style positions. They basically say, it looks a bit odd and doesn't fit our calculations too well, but the closer we look the more real it looks. So we are going to say it looks like global warming is doing this, but we will keep an open mind and keep looking. The debunkers are taking a position that sounds like politics. It is made up of clear-cut answers with good sound bites. This is not to say we don't have political types on the pro-global warming side, there are lots of them. But the lead scientists publishing the recent "seems like global warming" articles talk like scientists, and I think they are.
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http://zfacts.com/p/227.html | 01/18/12 07:23 GMT
Modified: Fri, 21 Apr 2006 21:58:25 GMT
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