Thursday, August 9, 2007

Reading Challenge XIII

Today's selection: Frequently Asked Questions (From the 4th IPCC Assessment Report.

Hardly economics, I know, but without variation, one starves.

Commentary: Not as complex a document as I would have liked. I would have preferred 'this is why the adjustment for urban heat island effects is correct' as opposed to 'urban heat island effects have been compensated for'. However, it still does a pretty good job of answering any basic questions one might have about climate change. There are also a lot of punchy graphs, if you're into that kinda thing.

Some interesting points:
1) The night has been warming considerably more rapidly than the day in recent years.

2) While sea ice in the Northern Hemisphere has been well below historical values recently, Southern Hemisphere sea ice has increased.

3) Thermal expansion of ocean water is an equally important contributor to sea level rise as is the melting of ice.

4) Cement manufacture is a staggeringly large contribution to CO2 output. Enough so to be listed alongside fossil fuel combustion as the two major CO2 sources.

5) It is possible to identify human-produced CO2 in the atmosphere as opposed to the natural variety, ours being characterized by more C-13 and less C-14.

6) The methane concentration has stabilized in the atmosphere for the last two decades.

7) A volcanic forcing can drop the global mean temperature by half a degree celsius.

8) We can have much more confidence in climate models than in economic models.

9) Mr. Gore's potential "turning off" of the Gulf Stream is not likely.
Catastrophic scenarios suggesting the beginning of an ice age triggered by a shutdown of the MOC are thus mere speculations, and no climate model has produced such an outcome. In fact, the processes leading to an ice age are sufficiently well understood and so completely different from those discussed here, that we can confidently exclude this scenario.

10) However, unsure about West Antartica or Greenland breaking up:
Ice sheet models are only beginning to capture such small-scale dynamical processes that involve complicated interactions with the glacier bed and the ocean at the perimeter of the ice sheet.

11) Since CO2 does not break up in the atmosphere like methane or nitrous oxides, immediately halving CO2 emissions would stabilize CO2 concentration for less than a decade, at which point it would start increasing again.

Well, I guess that chemistry scholarship I won had some use, even if I did jump ship for economics. Of course, the only reason I'm an economist, not a chemist, is because I didn't win another chemistry scholarship to go to England for two weeks. Figured there was less competition in economics.

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