Science Questions

Is the southern hemisphere cooling?

A lot of smart people think global warming is just part of a natural trend that humans have very little influence on. One person points out the fact that it's actually getting colder in the southern atmosphere, and in Antarctica the ice sheet's thickening in places. How do you account for that? Jeff via email

'm afraid I can't even give you comfort there. Although parts of the Antarctic haven't shown a very strong warming yet, maybe because they're so isolated from the rest of the atmosphere, the Antarctic Peninsula for example, has been warming very fast. It's one of the places that has been warming the most rapidly. We now think that probably is related to global warming. We weren't really sure before because despite what you may think, we Scientists are cautious people. So the rest of the Antarctic hasn't yet shown a very strong cooling but the models suggest that it will. It is actually true that the ice sheets under warming probably will get thicker at first because what happens is around the edges where it's warmest, it will start to melt. But in the centre the temperature is nowhere near that, so it won't start to melt in the centre and you get a little bit more snowfall when it's warmer so that does make it a little bit thicker in the centre. Unfortunately all the predictions are that what happens at the edges wins.

January 2007