Which time interval should we look at? You know that if we start in 1940, we would see some kind of cooling trend. Such a conclusion would be politically incorrect. We really want to start roughly in 1978 to see the global warming. OK, so let's see the scary truth in the most transparent light. Take the data from University of Alabama from the URL
junkscience.com had to do it for us). For troposphere, you will obtain the following graph - click the picture to zoom it in and tell me what your impressions are.
What are your reactions? My reactions are the following:
- 1998 was a pretty warm year
- well, it was because of the 1997-98 El Nino
Junkman has also drawn the graph of the surface temperatures here and I guess that you won't be surprised that we may be heating the surface a bit. On the other hand, stratosphere seems to be cooling quite clearly, as NASA's satellite graphs show. I am certainly not claiming that the cooling of the stratosphere proves that the global warming theory is wrong; it does not prove that it is correct either. They usually say that the cooling comes from ozone depletion:
The GHCC people from NASA are, of course, cautious, and they don't use simplified cliches such as that they have proved global cooling. Instead, they say that the answer about the existence of human-induced greenhouse global warming is not clear.
Even if one forgets about the apparent discrepancies of the troposphere temperatures and works with the living-room-like surface data, it is questionable whether the trend goes beyond the historic variability - the hockey stick graph seems to be probably wrong, too. Nevertheless, many people like to claim that there is enough consensus to cripple the world's economy - the main evidence they have is that there exists one human-induced contribution to the global temperature whose sign seems to be positive according to the idealized model - one contribution among hundreds of other and larger contributions that are ignored.
Cooling of the stratosphere
The comments under the article led to various questions - for example, does the troposphere have to warm up if the greenhouse global warming theory is correct? The answer is, of course, "yes". The greenhouse effect means that the troposphere - the lowest layer of the atmosphere where most of "weather" takes place - is absorbing the thermal radiation emitted from Earth's surface via its water vapors and perhaps other greenhouse gases. Therefore it must be heating up if it absorbs more. In fact, according to the global warming models, the warming trend must increase with the distance from the surface.
Of course, it is completely essential for the global warming theory to find a proof that the NASA data mentioned above are incorrect. This is what various people - such as Qiang Fu - argued. Fu argued that one must add a positive contribution to the present temperature of the troposphere in order to agree with the global warming theory, and such an extra contribution may be justified by the cooling of the stratosphere that may be "artificially" lowering our data from the troposphere. In other words, he simply adds a piece of the cooling stratosphere with a significant negative weight, to "improve" the warming of the troposphere.
Roy Spencer from Alabama who is - together with John Christy - the most experienced guy in the satellite temperature measurements claimed that the paper by Fu was rubbish and that it did not appreciate some exact methods and insights that the Alabama guys made decades ago. Qiang Fu then published another paper in Nature defending himself at the end of 2004, while some other papers attacked his work - and the Saga continues. I am not capable to make unique conclusions who of them is right and how much - that would be just guessing based on the fact that Roy Spencer just looks much brighter to me - but I hope that it is enough to see that as of the end of 2004, the question whether the troposphere is warming enough to agree with the global warming theory is open.
Incidentally, Roy spencer also wrote about the green reaction to the tsunami here. He also explains why the current climate models are not trustworthy here.