After months of reading reports of ice melting in the Arctic, the media attention seems to have switched to the southern hemisphere with a series of stories about changes to the ice in Antarctica. I guess it makes sense that the focus of attention would be in the northern hemisphere at the end of the northern hemisphere summer and then switch to the southern hemisphere at the end of the southern hemisphere summer (just about now). New Scientist, Issue 2703 [11 April 2009] carries a short item on the collapse of an ice bridge that connected two islands to the Wilkins ice shelf which has left the shelf vulnerable to the action of the ocean. The observations (from satellite images) show that ice shelves can very quickly become unstable. However, it is not just short timescale changes that are in the news, as the same issue of New Scientist has an article about the changes undergone by Antartica’s ice over millions of years. The article describes how ice cores have revealed huge fluctuations in the ice over geological timescales. The findings are important for climate modelling and the initial suggestion is that rates of sea level rise in the near future could be larger than currently predicted.
Remaining on an Antarctic ice theme, New Scientist, Issue 2705 [25 April 2009] reports on new research which offers an explanation for why Antarctic sea ice seems to be growing in extent even though global temperatures are warming. Apparently the answer lies with the hole in the ozone layer which results in changed weather patterns around Antarctic which have created stronger cold-air storms which have enhanced sea ice formation in certain regions. The report notes that as the ozone hole closes this effect will die away and Antarctic sea ice should start to do what it ought to do in a warming world, namely, melt.
Tim O'Hare 