DADvocate

The other day at DrHelen, I made a comment that may be more true than I expected.

The article says, globally, February was the warmest ever. It sure wasn't in Cincinnati. Average temperatures were more than 11 degrees F. below normal. It makes me wonder, at least a little bit, how they come up with these "global" temperatures.

Emphasis added

We all may have very good reason to wonder about "global" temperatures. It turns out whatever method being used to calculate "global" temperature may not be valid. Science Daily published this article March 18, 2007: Researchers Question Validity Of A 'Global Temperature'.

Discussions on global warming often refer to 'global temperature.' Yet the concept is thermodynamically as well as mathematically an impossibility, says Bjarne Andresen, a professor at The Niels Bohr Institute, University of Copenhagen, who has analyzed this topic in collaboration with professors Christopher Essex from University of Western Ontario and Ross McKitrick from University of Guelph, Canada.

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"It is impossible to talk about a single temperature for something as complicated as the climate of Earth", Bjarne Andresen says, an an expert of thermodynamics. "A temperature can be defined only for a homogeneous system. Furthermore, the climate is not governed by a single temperature. Rather, differences of temperatures drive the processes and create the storms, sea currents, thunder, etc. which make up the climate".

He explains that while it is possible to treat temperature statistically locally, it is meaningless to talk about a a global temperature for Earth. The Globe consists of a huge number of components which one cannot just add up and average. That would correspond to calculating the average phone number in the phone book. That is meaningless. Or talking about economics, it does make sense to compare the currency exchange rate of two countries, whereas there is no point in talking about an average 'global exchange rate'.

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These are but two examples of ways to calculate averages. They are all equally correct, but one needs a solid physical reason to choose one above another. Depending on the averaging method used, the same set of measured data can simultaneously show an upward trend and a downward trend in average temperature. Thus claims of disaster may be a consequence of which averaging method has been used, the researchers point out.

What Bjarne Andresen and his coworkers emphasize is that physical arguments are needed to decide whether one averaging method or another is needed to calculate an average which is relevant to describe the state of Earth.

Seems we've still a lot of work to do in order to determine what is going on climatically and how much impact Al Gore's excess CO² is having on the climate.