/ 8 July 2009

Sea ice is slowly disappearing

Summer sea ice could be gone by 2080, says the International Polar Year (IPY), a scientific programme organised through the International Council for Science and the World Meteorological Organisation.

”There is a probability that summer sea ice disappears before 2040, possibility within the next decade,” said Dr David Carlson, director of the IPY’s international programme office.

Carlson was speaking at the United Nation’s climate change talks in Bonn recently, which hoped to turn the tide on the melting of the cryosphere — those areas where water is frozen, such as the Arctic.

Pam Pearson, an Arctic pollution expert from the Climate Policy Centre, said melting was occurring more rapidly than previously thought.

Earlier this year the Arctic Council — an Arctic science organisation — said that if melting in the Greenland ice sheet continues global sea levels could rise one metre by 2100. The World Glacier Monitoring Service said glaciers lost about 12m of water between 1980 and 2007. Recent reports show Antarctica is losing mass.

But the danger goes beyond the sea ice, ice sheets and glaciers. Carlson said that the permafrost — ground that’s frozen for more than a year — is also changing rapidly. It holds more carbon than the temperate and tropical forests. If the permafrost melts, it will release carbon dioxide and methane into the atmosphere, further contributing to global warming. And scientists now say melting permafrost is also linked to sea ice loss. ”The faster the permafrost disappears, the faster the sea ice disappears,” said Carlson.

Another issue that scientists are keen to raise is black carbon deposition. Black carbon — or soot — is a byproduct from incomplete combustion. These tiny particles travel to the poles and coat the ice, making it darker. Darker ice is less reflective so it absorbs more heat and causes further melting.

Black carbon is not regulated under the climate convention and efforts to bring the issue into formal negotiations on climate change have failed. Pearson said this is because countries fear black carbon would then need to be recognised as a gas. ”For policy-makers, you need to be able to speak about cost-benefit and right now we can’t do that.”

Jean-Pascal van Ypersele, one of the vice-chairs for the Intergovernmental Panel on Climate Change, said the organisation has considered the issue of melting ice. He said the panel’s fifth assessment report — which will inform further negotiations on climate change — will deal with ”every aspect of the cryosphere, including black carbon”.

The panel hopes to organise meetings with the scientific community and sea-level rise has been identified as an issue to be covered.