Wednesday, April 04, 2012

Ice capades

For decades now, I have watched climate scientists at work, vicariously though my daughter's membership in that community. I have not detected any disposition to interpret data one way or the other because of self-interest, peer pressure or conspiracy. Indeed, I watched Mo take on the establishment with her tectonic uplift theory for the ice ages (which was subsequently the subject of a Nova program). The theory would rise or fall with the data. It rose.

That's what peer review, reproducibility, and independent evidence is all about.

Her latest paper (Nature, March 22) provides further evidence that climatologists are not willy-nilly stirring up worst-case scenarios of global warming disaster.

There is evidence on the ground in Bermuda and the Bahamas that sea level during an interglacial warming 400,000 years ago was 20 meters higher than today. Such a rise can only be accounted for by the catastrophic melting of the massive East Antarctica ice sheet (or perhaps a super tsunami).

A 20-meter sea-level rise! Now that would be something to worry about. You could gondola through the streets of New York and board and disembark through third-story windows. Venice would swim with the fishes.

But wait. The Earth is rather like a hard rubber ball. Squeeze it in one place, it bulges out in another. Put heavy ice caps on the northern continents and the underlying crust sinks. Away from the ice caps, in Bermuda and the Bahamas, it rises. Melt the continental ice during an interglacial and the crust rebounds there and sinks elsewhere. At least half of that apparent 20-meter sea-level rise was because of crustal subsidence. The East Antarctic ice sheet did not collapse.

Well, that's a quick explanation; here's another description. The evidence and data analysis are in the Nature paper.

So, friends, it would appear that the East Antarctic ice sheet is not about to melt anytime soon. The worst case global-warming scenario has been mitigated. Instead of stepping out of your gondola at the third floor of your New York destination, you can disembark on the second story.