22-27 April 2012, Montréal, Canada

From Knowledge to Action

Antarctica and the Global Climate System

The ozone hole over Antarctica has intensified a ring of winds around the South Pole, known as the polar vortex, causing an increase in westerly winds over the Southern Ocean in summer and autumn and altering weather patterns around the Earth's southernmost continent. As a result, most of the Antarctic has been shielded from "global warming" to date, a situation that won't continue, says the landmark report Antarctic Climate Change and the Environment (ACCE). As ozone concentrations above the region recover over this century, the greenhouse gases that fuel climate change are predicted to warm Antarctica by around 3°C during this century and cause a decline in sea ice of about one-third.

This is but one key finding of ACCE, which documents the latest knowledge of the Antarctic based on research by 100 world-leading scientists from eight countries. Published by the Scientific Committee on Antarctic Research (SCAR) in 2009, the report is a key outcome of Antarctica and the Global Climate System (AGCS), a major research program that is exploring the nature of, and mechanisms involved in, atmospheric–ocean linkages between the climate of the Antarctic and the global climate system.

The scientific findings in this 555-page report are indicative of the issues that will be on the agenda at the IPY 2012 Conference From Knowledge to Action, which will explore how the knowledge gained from International Polar Year (2007-2008) and recent polar science can help inform actions and policies to address critical global issues.

"Even relatively subtle changes in the atmospheric and oceanic circulations in Antarctica and the Southern Ocean may be important in determining global climate evolution. For example, there is good evidence to suggest that the rate at which the Southern Ocean overturns is a key factor in establishing the balance of carbon dioxide between the global atmosphere and oceans, and that the atmospherically driven supply of ocean heat to the Antarctic ice shelves influences their melt rate and global sea level change," says Dr. Alberto Naveira Garabato, chair of the AGCS Steering Committee and physical oceanographer based at the National Oceanography Centre in Southampton, U.K.

Other key findings of the report include :

1. Atmospheric concentrations of carbon dioxide (CO2) and methane (CH4), both greenhouse gases, are at higher levels than experienced in the last 800,000 years and are increasing at rates unlikely to have been seen in the geologically recent past.
2. The Antarctic Circumpolar Current, the largest ocean current on Earth, has warmed faster than the global ocean as a whole. If temperatures continue to rise, non-indigenous species may migrate into the region, competing with and replacing original Antarctic inhabitants. Key species could suffer from ocean acidification and biodiversity of the Antarctic seabed may decrease.
3. Parts of the Antarctic are losing ice at a rapid rate. Warmer ocean temperatures have caused significant thinning of the West Antarctic Ice Sheet. Overall, 90% of the Peninsula's glaciers have retreated in recent decades.
4. Meltwaters from retreating ice sheets contribute to global sea level rise, which is projected to increase by up to 1.4 metres or more by 2100. West Antarctic ice loss alone could contribute some tens of centimetres to this sea level rise.
5. There has been a 10% increase in Antarctic sea ice extent and a contrasting decrease in sea ice west of the Antarctic Peninsula.
6. Rapid warming along the western Antarctic Peninsula, along with a switch from snowfall to rain during summer, has led to an expansion of plant, animal and microbial communities in newly available land.

"The work of the AGCS community, as represented by the ACCE report, highlights the complex repercussions that the uncontrolled global 'experiment' we are conducting is likely to have on Earth's climate and ecosystems, and thus has significant implications for climate change mitigation policies," says Dr. Naveira Garabato.

To sign up for the IPY newsletter, please contact: .

Return to TOP NEWS