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Press Release: 8 June 2005

Antarctica: Rats, Cats and Climate

On June 8, two scientific experts present their ideas to the King of Sweden and the national delegations attending the Antarctic Treaty Consultative Meeting (ATCM), Stockholm, 6-17 June, 2005. The experts represent the Scientific Committee on Antarctic Research (SCAR), the body that advises the ATCM on science. SCAR´s work adds value to national efforts through international cooperation [see separate briefing note on SCAR].

The SCAR Revolution (by Professor Jörn Thiede, Alfred Wegener Institute, Germany)

Antarctica is the highest, windiest, driest, coldest, iciest, emptiest, cleanest, quietest place on Earth, home to no-one, save a few thousand scientists, but visited by a growing number of tourists. Professor Thiede, the President of SCAR, explains that it is nevertheless a vital part of the Earth’s climate system and the global ecosystem. He shows that scientific studies in Antarctica and the Southern Ocean are critical to analyse the Earth system as a whole and to understand, as well as to forecast future changes.

One of SCAR´s primary objectives is to describe the past, understand the present and predict the future. Despite years of study, there remain a number of key scientific questions. The deep ice cores from the Antarctic ice sheet are Earth’s finest climate archive. The latest results show a great range of change between cold and warm periods over the last 800,000 years, with a marked shift in the pattern of climate change about 450,000 years ago something we still do not fully understand. In recent times, we see spectacular events like the collapse of the Larsen ice shelf in 2002. We also observe that many of the glaciers in the Antarctic Peninsula are retreating. Are these happenings the result of the natural dynamics of the Antarctic ice cover, or a consequence of the global warming caused by man´s activities? The worry is that if warming continues, with the eventual melting of the West Antarctic Ice Sheet, this would cause incalculable consequences for the coastal regions of the world which are home to 30-50 % of humans. Strangely, East Antarctic shows no sign of melting. This is another of the apparent contradictions facing scientists as they try to unravel the role of Antarctic in the global climate system. SCAR is helping to clarify what exactly is going on.

Aside from its obvious role in the climate system, Antarctica is home to some big surprises. One of the most astonishing and exciting findings is the occurrence of giant lakes buried under the Antarctic ice sheet. We have long known about the largest of these, Lake Vostok, which is the size of Lake Ontario. But in recent years many other subglacial lakes have been detected, and we now know of around 145. The waters in these lakes have been isolated from the air for many tens of thousands if not millions of years. Scientists believe they may contain many unknown organisms. To avoid contaminating the lakes during drilling, scientists and space engineers are currently working to develop a new drilling technology, which will be first used for one of the smaller subglacial Antarctic lakes.

Biodiversity: Moves in Life´s Grand Game (by Professor Steve Chown, University of Stellenbosch, South Africa)

Professor Chown talks about the exciting scientific questions concerning the evolution of life in response to the changing climatic conditions in Antarctica and the Southern Ocean. He explains that once upon a time, dinosaurs roamed the continent and swam in its seas. Since then, life evolved as the climate cooled. But, nowadays humans are having a profound effect. Antarctica and its surrounding Southern Ocean are being invaded by a wide range of alien species. These include microbes, algae, fungi, bryophytes, land plants, invertebrates, fish, birds and mammals. These species have come to survive, and in some cases dominate, terrestrial, freshwater, and marine habitats. In the sub-Antarctic islands they are causing considerable damage by altering local ecosystems. For example, rats and cats brought by ships have caused the disappearance of seabird species from several islands. The birds have returned when these alien species have been eradicated. It´s not only animals that cause trouble; alien plants can reduce local diversity by as much as 40%.

Alien species arrive in many ways: in clothing and personal baggage, attached to fresh vegetables, in vehicles, affixed to the hulls of ships and inflatable rubber boats, and as unwanted passengers on anchor chains, in sea chests and in ballast water.

Across the Southern Ocean islands there is a strong relationship between the numbers of humans that visit an island and the numbers of species that have been introduced and have become established. This relationship has been established elsewhere and seems to be a general rule. Recent increases in human activity in the Antarctic have been considerable. For example, in the 2001/02 season, Treaty Nations deployed 4,390 personnel at 67 stations or field camps in Antarctica. They also made use of some 60 ships, departing from 30 cities around the world, to offload personnel and cargo. Tourist numbers doubled from approximately 6,000 in 1992 to 13,600 ten years later, and last season (October to March 2004-2005) reached over 24,000, most of whom visited the Antarctic Peninsula. Over the past 10 years, the numbers of ships and passengers visiting South Georgia have increased 3-4 fold. In 2004/05 over 9,400 people visited one small site: Port Lockroy.

It is not only the changes in numbers of visitors that is important. In the Antarctic Peninsula Region, and on many sub-Antarctic islands, the climate has warmed dramatically over the past 50 years. That means that these environments are now less hostile than they once were to new species. The chances of successful colonization of the Antarctic region by alien species are likely to increase substantially with more visitors and with yet more warming, unless appropriate mitigation measures are put in place. Prevention is more economically viable than eradication programmes, which are usually expensive, often long-term, and may prove inadequate. The scientific evidence suggests the need to develop a new strategy for Antarctic conservation in the 21st century.

Further details contact: Colin Summerhayes, Executive Director, Scientific Committee on Antarctic Research (SCAR), Scott Polar Research Institute, Lensfield Road, Cambridge CB2 1ER, UK
Tel: +44 1223 336542, Fax: +44 1223 336550 E-mail: cps32@cam.ac.uk

The SCAR web site is at www.scar.org