The Earth's climate is changing. This is nowhere more apparent than at the poles, where many areas are warming at a rate two or three times the global average.

In 1995, the United Nations-affiliated Intergovernmental Panel on Climate Change (IPCC) finalised its second scientific assessment, concluding that "the balance of evidence suggests a discernible human influence on global climate... the observed warming trend is unlikely to be entirely natural in origin."[FOOTNOTE: Intergovernmental Panel on Climate Change (1995): Report to IPCC from Working Group I: policy-maker's Summary of the Scientific Assessment of Climate Change, Cambridge University Press, June 1996]

Climate scientists have long predicted that the increase in greenhouse gases from human activities would cause the most rapid and dramatic climatic changes in polar regions. It is to draw attention to the first signs of those changes, now discernible in the Antarctic Peninsula, that Greenpeace is travelling to Antarctica. In January 1997 the Greenpeace ship MV Arctic Sunrise will document a frozen continent that is thawing around the edges.

What's Happening at the Poles

The polar regions are crucial for the global environment in many ways. They contain much of the world's remaining large tracts of wilderness areas. They have profound effects on the global climate. And they are significant indicator regions, showing up climate changes before they can be detected elsewhere.

In March 1994, the fastest sustained atmospheric warming since world-wide temperature records began 130 years ago - 0.5 degrees Celsius per decade since 1947 - was reported in the Antarctic Peninsula by British Antarctic Survey (BAS) scientists. BAS spokesperson Dr John King stated at the time: "The rise is the fastest we have on record ... people should be looking to the future for the consequences could be quite dire."

Apparently as a consequence of the observed warming, vast areas of ice shelf, the large floating masses of ice surrounding the continent's grounded ice sheets, are disintegrating along the coastlines of the northern Antarctic Peninsula. As air and sea temperatures increase, the line of average temperatures above which ice shelves are no longer viable is moving inexorably southward.

Other changes, such as the disappearance of penguin colonies and the spreading of colonies of flowering plants, are occurring on a smaller scale, but are no less real. Stands of the small flowering pearlwort and Antarctic hair grass, the only higher plants in Antarctica, are now found further south, and new species are also appearing as melting ice frees long-trapped seeds. Penguin colonies are declining dramatically - apparently because their main food source, krill, is being affected by the decreasing sea ice cover. Seal populations are moving south, and in so doing are themselves disrupting previously undisturbed moss beds.

These changes are obviously significant for the frozen continent because they threaten major disruptions to the region's delicate ecological balance. They also help to validate the scientists' predictions. They are the first signs of the global changes to come.

Implications for the Rest of the World

The full effects of the warming on the Antarctic climate are complex and not yet fully understood. However, they extend well beyond the Antarctic region itself, and may well have dramatic global repercussions. The warming itself may cause further accelerated warming, or a "positive feedback". For example, the loss of sea-ice reduces albedo (reflection) and changes the ability of the ocean to absorb carbon dioxide and heat. Sea level rise associated with increased discharge from the ice sheets represents one of the greatest threats from human- induced climatic change. While we do not yet know if the melting ice in Antarctica is already contributing to sea level rise, it is looking increasingly likely that it will do so in the future. The potential collapse of the entire West Antarctic Ice Sheet must also be considered. The risk currently remains unquantified, but the consequences would be catastrophic - certainly contributing to the destruction of the small island nations of the Pacific, Caribbean and Indian Ocean.

In early 1991, Australian Antarctic researcher, Dr Bill Budd, suggested a feedback link between climate change and Antarctic ozone depletion. Warming lower atmospheric temperatures cause decreasing temperatures in the upper atmosphere, further exacerbating stratospheric ozone loss. Meanwhile, US researchers have found that increased UV-B levels, consistent with the severe spring ozone "hole" over Antarctica, can result in decreased productivity in phytoplankton, a major link in the short Antarctic food web.