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Orwell (another) discussion on global warming

Lately I have (again) becoming embroiled in a debate Blog Vietti about global warming.

And I heard the usual arguments corny as to why there is no heating globable and if there is not anthropogenic. Answer here, so I'm not going to visit every day for a discussion on air Vietti fried.

Objection 1: There is no heating. The data show that the heating does not apply because they use a size, the average temperature of the earth, which makes no sense.

that of non-existence of the average temperature is one of the favorite arguments of the deniers of global warming. We put the record straight from a thermodynamic point of view: what does not exist is the earth's temperature, because the land is not a system in thermodynamic equilibrium and therefore does not have a temperature per se.

An average temperature on earth, however, is something different. We agree that it is reasonable to say: "This morning there were 18 degrees in Rome." Again, technically, This does not make sense because "Rome" is not a system in thermodynamic equilibrium. However, we know what this phrase means: take the various temperature sensors in Rome and is the average (perhaps weighted) at some point of the day. This number we call "average temperature". Now, this is a stochastic process, so this average temperature in Rome will change over time. 18 ° C this morning, tomorrow 20 ° C. As a good stochastic process will have an expected value, no? This expected value, we call the annual average temperature in Rome.

(Now I'm not a meteorologist, so maybe the details are different, I just wanted to point out that there is nothing absurd to speak of a temperature average).

Objection 2: Climate scientists have so far made only predictions wrong, so wrong in the future.

Apart from the obvious absurdity inherent in this topic, it is simply not true that climatologists have made wrong predictions.

Over the past 30 years the average temperature has risen approximately 0.2 ° C per decade

http://en.wikipedia.org/wiki/Global_warming

There are a number of articles of the '70s and '80s in which warming predicted to exactly this size, there Linko 2, signals the next (large) number of citations articles were collected to show how main stream and have not gone to look for things too favorable (I have used, among other things, less than 5 min).

Dickinson, Cicero, Nature (1986) (mentioned 384 times on Scholar)

Hansen et al., J. Geophy. Res (1988) (mentioned 612 times on Scholar)

Another interesting thing: in 2007 Rahmstorf and others had already done such work, or to compare the predictions made from '90 onwards with data actually collected, with the result that the forecasts tended to underestimate the size of global warming.