22-27 April 2012, Montréal, Canada

From Knowledge to Action

Antarctica Holds Clues to Future Global Changes

Climate-related changes underway in the Earth's coldest, driest, windiest and southernmost continent, Antarctica, will inevitably have impacts around the world. Finding ways to address the regional and global consequences of such changes will be on the agenda at the IPY 2012 Conference From Knowledge to Action, taking place in Montréal, Québec, Canada from April 22 to 27, 2012.

Variations in the Antarctic ice sheet, which has existed for some 35 million years, has been one of the major driving forces of climate and global sea level changes throughout the Cenozoic Era, from 65.5 million years ago to present day. It is of vital importance to understand the response of large ice masses to climatic forcing — the mechanisms that cause climate change — since fluctuations in ice-volume can have significant impacts on the Earth's climate system through a variety of physical and chemical feedbacks.

Since 2004, the international and interdisciplinary Antarctic Climate Evolution (ACE) project has played a central role in developing major scientific programs that explore the response of the cryosphere — the part of Earth's surface that is seasonally or perennially frozen, including snow, frozen ground, ice on rivers and lakes, glaciers, ice caps, ice sheets and sea ice — to paleoclimate changes.

"Changes in ice-volume affect global sea level, the formation of sea ice, ocean bottom-water production, Southern Hemisphere winds, and the capacity of ice sheets and sea ice to act as major heat sinks and insulators," says Dr. Carlota Escutia of the Spanish National Research Council-University of Granada and co-leader of ACE, which is being carried out under the auspices of the Scientific Committee on Antarctic Research (SCAR).

Geophysical and geological records, which hold clues to the onset and response of the Antarctic ice sheets to past climate changes, are being analyzed and integrated with coupled climate, ocean and ice-sheet models to gain insight into climate and ice sheet variability and the forcing mechanisms that control future change and ice sheet responses.

According to the report Antarctic Climate Change and the Environment, published by SCAR in 2009, changes are already well underway in Antarctica, including :

1. Parts of the Antarctic are losing ice at a rapid rate. There has been significant thinning of the West Antarctic Ice Sheet, as well as a few smaller coastal areas in East Antarctica. Loss of ice from the West Antarctic ice sheet is projected to contribute some tens of centimetres to overall global sea level rise by 2100.
2. Ice core studies show that atmospheric concentrations of carbon dioxide (CO2) and methane (CH4) — both greenhouse gases — are at high levels unprecedented in the last 800,000 years, and that concentrations are increasing at rates that have probably not been seen in the geologically recent past. Geological records of deep time show that, previously, high atmospheric CO2 levels have led to temperate climates, transient ice sheets, sea level changes in the order of tens of metres and out-gassing of methane hydrates.

"Among its accomplishments, ACE has advanced our knowledge climate variability over the past 10,000 years using evidence such as sediment records that could help to discriminate between natural climate variability and anthropogenic influences," says Dr. Escutia. "In addition, records of warmth and extreme warmth older than 2 million years could provide physical evidence of the potential response of the Antarctic ice sheet to climatic scenarios that might arise in the mid-21st Century."

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