Debate

From: [email protected] <[email protected]>
To: [email protected] <[email protected]>
Date: 09. december 1997 10:18
Subject: Re: CC Digest, 9/12/97

Global Warming: Both Sides of the Argument Could be Wrong
From: Jonathan Shanklin <[email protected]>

Benny,
A few points on the subject. The concensus view on global warming is that from the IPCC: The balance of evidence suggests that increased greenhouse gases are having an effect. There is the possibility that the IPCC is wrong, but they could be wrong in either direction. Vociferous minorities are just that and they exist on both sides of the debate. They do little to enhance the public view of science. Some parts of the world have definitely warmed. The Antarctic Peninsula is a case in point where the mean annual temperature has risen by 2.5 deg C over the past 50 years. We think that this is a regional effect, but only on the basis that global climate models don't suggest that the area is unduly sensitive to global warming. The effect can be seen in decaying ice-shelves and increased vegetation (albeit in one form of grass). Regional changes should not be used to validate or invalidate global changes unless there are very good scientific reasons for doing so.

The view of GLOSS is that global sea level has risen 10 - 25 cm in the past century. These are objective measurements made on an international basis. I think it is worth pointing out that NASA satellites failed to detect the ozone hole, although it was there in the data once they looked for it. It must be realised that almost by definition satellites use cutting edge technology which is very difficult to use for detecting long term changes. Each new sensor tends to be different and makes measurements in a different way. Satellites are very good for getting a global view of what is going on 'now'.

It is true that the majority of climatologists do not consider solar variation as a factor in their models. This does not invalidate the models or the predictions, but it does make interpreting past climate and predicting future climate more uncertain. Finally it does not really matter whether the predictions of global warming are right or wrong. What is undeniable is that we are using up resources, which have a finite lifetime, in a wastefull and thoughtless fashion. This is what needs to change.

Jon Shanklin
[email protected]
British Antarctic Survey, Cambridge, England
http://www.nbs.ac.uk/public/icd/jds