Climate change and evolution
OUR topics this morning are global warming, evolution and feathers. Let's start with the warming. Despite a frenzied last-minute drive involving snowstorms in Europe and the eastern United States, planet Earth failed to save itself from another last-place finish in 2010: once again, it was the least cold year on record. The World Meteorological Organization announced its finding last week that global mean temperatures for the year were 0.53C above the 1961-1990 mean, 0.01C warmer than 2005 and 0.02C above 1998. With the comparison having a margin of uncertainty of 0.09C, the three years are considered tied for the hottest year on record. That followed results the previous week from NOAA, which found 2010 and 2005 tied as the hottest years ever, and NASA, which found the same thing. (They both think 1998 was a bit colder.)
By itself, as we always say, one hot year doesn't prove anything. The fact that every one of the twelve hottest years on record has come since 1997 is a little harder to wave away. 2010 was also the wettest year ever, corresponding to the expectation that higher heat means more water vapour. More countries set national high-temperature records in 2010 than ever before, including the biggest one, Russia. Arctic sea ice in December was at its lowest level ever, temperatures across a broad swathe of northern Canada have been 20 C higher than normal for the past month, the record temperatures are coming despite the lowest levels of solar activity in a century and a La Nina effect that should be making Canada colder rather than warmer, and so on. It is of course possible that global warming plateaued this year; it's also possible that it plateaued this morning. One can always hope! For now, though, this is the basic shape of things:
The George Will "global warming has ended" moment shows up as that little dip towards the end, before it returns to trend. So, what effect will the new data have on that meme? Quite possibly none. People who tried to cast doubt on global warming in 2009 based on a few years one could isolate so that they didn't show a discernible trend will now no doubt respond that a couple of very hot years don't prove anything. Which underlines how often the conclusions one draws from data are determined by a combination of the hypotheses you're framing, and at what point you start looking.
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