Thursday, November 12, 2009

Do I Sound Like a Broken Record?

(copyright U.C.A.R., graphic by Mike Shibao)
Andrew Revkin has a piece on the changing ratios of record high to record low temperatures. In it he quotes a bit from the National Center for Atmospheric Research:
If nations continue to increase their emissions of greenhouse gases in a “business-as-usual” scenario, the U.S. ratio of daily record high to record low temperatures would increase to about 20 to 1 by midcentury and 50 to 1 by 2100. The midcentury ratio could be much higher if emissions rose at an even greater pace, or it could be about 8 to 1 if emissions were reduced significantly, the model showed.
Note that even with global climate change, there will still be the occasional cold record broken. This is a perennial argument from the deniers: "Global warming must be false, because it's cold." Well, yes, it's still going to get cold from time to time. Sometimes that's expected variation, sometimes it's because warming itself increases the temperature gradient and causes cold air to move to lower latitudes more rapidly and vigorously than it could have in a non-anthropogenic climate.

For example, from today's Telegraph, we have this guy:
However Prof Plimer said the world has experienced three periods of cooling since 1850 and furthermore carbon dioxide was increasing during many of those cooler periods.
And guess what? He is in fact a PhD-holding geologist! And he argues that there has been major climate change throughout Earth's history! And he's right: there has! And every one of those for which we've been able to get reliable atmospheric composition data has shown a striking correlation between CO2 concentration and temperature. And he's also right that there have been cooling periods interspersed with the warming periods over the last 150 years- you can see one in the above chart during the 60's and 70's. JUST AS YOU WOULD EXPECT!


Just to make sure that I do sound like a broken record, here's a picture I posted two months ago:

No comments: