Key Antarctic mission goes ahead

Abstract

Two vast East Antarctic regions that may be vital to the outcome of global warming are under new scrutiny. Nigel Williams reports. Two vast East Antarctic regions that may be vital to the outcome of global warming are under new scrutiny. Nigel Williams reports. As the Antarctic summer arrives an international team of researchers is set to embark on a mission to study two vast subglacial basins in eastern Antarctica that are both little studied but of potentially huge importance for sea levels under climate change. The polar regions are expected to warm significantly as a result of human-induced climate change because of positive feedback associated with melting ice and snow. Several studies have noted a rise in Arctic temperatures over recent decades, but it has been difficult to pin this down to human activity rather than natural variability. In the Antarctic, temperature trends are less clear, and indeed the International Panel on Climate Change consider the continent to be the only one where anthropogenic temperature changes have not been detected so far. But satellite evidence on the snow and ice build-up on Antarctica, which causes the ice to be pushed out to sea, suggests that between 1993 and 2003 there was a 12 per cent increase in this movement, which may result from more rapid melting. And a new study, led by Nathan Gillett at the University of East Anglia, published online in Nature Geoscience, finds just such evidence of human influence in both Arctic and Antarctic temperatures, making the new survey even more timely. The international team believe the barely observed Aurora and Wilkes subglacial basins could represent a key component of the vast East Antarctic ice sheet — the largest remaining body of ice on Earth. The two basins together comprise an area equivalent to Mexico. Until recently, the East Antarctic ice sheet, which covers the two basins, has been considered a stable ice reservoir, unlikely to contribute to sea-level rise in the near future. But if climate change is occurring and temperatures are rising, as recent studies suggest, thawing of the east Antarctic ice sheet could lead to sea-level rises of several metres, which would be devastating for coastal environments and communities around the world. The new study has been prompted by indications from researchers at Australia's Casey Station which suggest the subglacial basins could make the East Antarctic ice sheet more vulnerable in a warming world. Satellite data suggest that the Totten Glacier, which dominates the ice of the Aurora subglacial basin, appears to be losing ice at its downstream edge.“We are getting more science done with less oil using this old airframe with modern engines” “We are getting more science done with less oil using this old airframe with modern engines” In the past, scientists surveying the Antarctic ice sheets relied either on heavy cargo planes with poor fuel efficiency but long range, or lighter planes with better fuel efficiency but short range. With the plane designed for the current studies, the team have upgraded an old Second World War DC-3 with a suite of geophysical instruments to map the thickness of the ice sheet and measure the texture, composition, density and topography of rocks below the ice. “We are getting much more science done with less oil using this old airframe with modern engines,” said Don Blankenship, a research scientist at the Jackson School of Geosciences at the University of Texas at Austin, one of the invesigators involved. In December, the research team — Investigating the Cryospheric Evolution of the Central Antarctic Plate (ICECAP) — will fly the modified aircraft to begin the study. Data from the project will help model East Antarctic ice stability, forecast how ice might react to climate change, and show its potential impact on global sea level. The chemistry of the thick ice might also solve a mystery about past climate. Antarctic ice cores have already revealed aspects of the Earth's climate dating back 800,000 years. Farther back, around one million years ago, the Earth's climate changed in a way that caused ice ages to come and go much more rapidly than before. Researchers have long wondered what caused the shift. Australian researchers with ICECAP will search for sites to drill new ice cores with the potential to extend ice core records to beyond one million years.