Antarctica and Climate Change

Prof. Chris Rapley C.B.E., Director, British Antarctic Survey - www.antarctica.ac.uk, www.ipy.org

Life and its environment on Earth form a tightly coupled system. Understanding and predicting the way this system functions is a formidable scientific challenge. Given growing human impacts on the planet, it is also an urgent priority.

Antarctica is remote, inhospitable and without permanent inhabitants. It is the coldest, windiest, driest and highest continent. It is capped by an ice sheet up to 4 km thick and so heavy that it weighs down the surface of the Earth nearly 1km. In winter it is dark and surrounded by an area of frozen ocean larger than the continent itself.

Despite its geographic remoteness, the Antarctic is a pivotal component of the Earth system. It affects the planet directly through its influence on global climate and sea level. The cold, deep waters of the Southern Ocean reach northwards to affect Pacific, Indian and Atlantic oceans, and the seasonal variations in ice cover have a significant impact on the heat balance of the planet. The Southern Ocean supports economically important world fisheries, and scientific studies of these resources are essential for their sustainable management.

Antarctica's ice, rocks and living material contain a treasure trove of information on Earth's history and the evolution of life. Cores extracted from the ice sheet provide a detailed picture of the variations of greenhouse gasses and global climatic change over the last 900,000 years. They reveal that the chemical composition of the atmosphere and global temperatures are very closely linked, show how the patterns of the ice ages have varied with time, and reveal the very recent but significant impact of humans. Sediment cores from Antarctic lakes and the surrounding ocean extend the record back of hundreds of millions of years, to a period before the continents broke up and drifted apart to their current positions. Living organisms in the sea and on land have adapted to one of the most extreme environments on the planet, but one which has been relatively stable over the 30 million years since the Antarctic continent became isolated.

British Antarctic Survey (BAS) has committed itself to exploit the exceptional importance of the Antarctic and the surrounding Southern Ocean to achieve new insights into key global phenomena and scientific fundamentals. The aim is to gain new knowledge to inform policy and benefit society, and to do so on timescales which match the needs of national and international negotiations and legislative processes.

One issue of particular importance is the stability of the West Antarctic Ice Sheet. Most of this huge volume of ice, corresponding to a global sea level equivalent of 6 metres, rests on bedrock deep below sea level. Observations from satellites and aircraft show that it is currently discharging substantial quantities of ice into the ocean. But we do not know if this is a temporary burst of activity or if it represents the beginning of a collapse, - nor whether the ice loss results from natural variability or the long-range impact of human activities. New observations, both in the field, and sensed remotely, combined with improved numerical computer models, will provide the key to whether this part of the ice sheet is an "awakening" or "slumbering" giant.

Other issues include explaining and predicting the consequences of the dramatic warming that has taken place over the last 50 years on the Antarctic Peninsula, and the measures needed to limit damage to the Southern Ocean ecosystem, and the mortality of albatrosses in particular, as a result of human fishing activities in the region.

The inhospitable and hazardous nature of the Antarctic, its vast physical scale, and the challenges of operating in such a remote region of the planet, ensures that the ability to make major advances on all fronts lies beyond the means of any single institute or nation. Given this, the British Antarctic Survey has played an active role in developing and implementing international research collaborations. It has done so through the International Council of Science's Scientific Committee on Antarctic Research, and through the development of the International Polar Year 2007-2008.

The IPY 2007-2008 aims to carry out an intensive and internationally coordinated burst of high quality, priority research activities to lay the foundation for major scientific advances in knowledge and understanding of the nature and behaviour of the Polar Regions and their role in the functioning of the planet. It aims to leave a legacy of observing sites, facilities and systems to support ongoing polar research and monitoring, and especially to attract, engage and develop a new generation of polar researchers. A major goal is to engage the awareness, interest and understanding of schoolchildren, the general public and decision-makers worldwide in the purpose and value of polar research and monitoring.

For more information: CGRapley@bas.ac.uk