Antarctic melting to raise sea levels
December 2nd, 2009 by Jim JustA new report warns that by 2100 the sea level will rise by up to 1.4 meters — far exceeding the 0.59 meter rise predicted only two years ago by the IPCC in its 2007 4th Assessment Report.
SCAR scientists said that the IPCC underestimated grossly how much the melting of the Antarctic and Greenland ice sheets would contribute to total sea-level rises.
The report found that the hole in the ozone layer caused by the release of CFC (chlorofluorocarbon) gases has cooled temperatures and shielded most of Antarctica from global warming. Measures to control CFC gases will begin to “heal” the hole in around 50 to 60 years, leading to additional warming of about 3.0 Celsius (5.4 Fahrenheit) by century’s end. Even with the ozone hole, Antarctic ice sheets are already starting to melt.
The study also report the powerful Antarctic Circumpolar Current – which, by keeping warm ocean waters away from Antarctica enables that continent to maintain its huge ice sheet – has been warming faster than the global ocean as a whole. This is disrupting the region’s ecosystems, including enabling invasive species to compete with and replace native Antarctic inhabitants. That process has already begun on the Antarctic Peninsula. Sea ice loss and ocean acidification are directly affecting wildlife, and could reduce Antarctica’s rich biodiversity. Tiny krill at the bottom of the food chain have declined significantly, and in some areas Adelie penguin populations have dropped due to reduced sea ice and prey.
The report, Antarctic Climate Change and the Environment (warning – 20 MB) was prepared by the more than 100 scientists composing the Scientific Committee on Antarctic Research. The press release is available, as is a summary of the study’s top ten points.