Global warming melts Australia's glaciers
Planetark.org, Reuters News Service, June 4, 2001
SYDNEY - Australia's glaciers are melting.Scientists say the shrinking of Australia's little-known glaciers on remote, sub-Antarctic Heard Island in the Indian Ocean reveals global warming now stretches from the tropics to the edge of Antarctica.
"The recession of many glaciers during the past 50 years has been unprecedented in modern times for Heard Island," glaciologist Andrew Ruddell, with the Australian Antarctic Division, told Reuters on Friday.
"We can expect that with a warming world that this will progress further south. When we see warming going on this far south, we are always concerned about the Antarctic," he said.
Antarctic temperatures, averaging around minus 20 to minus 10 degrees Celsius (minus four to plus 14 degrees Fahrenheit), are still far too cold to show any significant effect from global warming.
"But we have seen break up of ice shelf in the Antarctic Peninsula region, and that is getting into the zero degree range because it is further north, so there is a slight change there," said Ruddell.
A five-month Australian scientific expedition to Heard Island which ended in March discovered global warming was dramatically changing the island's harsh and hostile environment.
Since 1947 the temperature has risen 0.7C (1.3F) causing glaciers to melt rapidly.
The island's 34 glaciers have decreased by 11 percent in area and 12 percent in volume - half the loss occured in the 1980s.
Brown Glacier was 6.3 km (3.9 miles) long in 1947, but has retreated 1.2 km (three quarters of a mile) by 2000, losing more than 26 percent of its area. The Jacka Glacier is half its length and the Stephenson Glacier has lost 27 percent of its area, exposing part of its bed rock.
"It's a very significant retreat. Glaciers are very sensitive to climate change," said Ruddell. "The rate of retreat is similar to New Zealand alps and European alps and Central Asia."
Recent studies of glaciers and ice caps in Tibet, Africa and Peru have shown dramatic reductions over the past few years due to global warming.
Photographs of Kenya's Mount Kilimanjaro in February showed its had lost 82 percent of its ice since 1912 and scientists calculate Kilimanjaro will lose its snow between 2010 and 2020.
Scientists say Heard Island, discovered by U.S. captain William Heard in 1853 and a former fur-seal hunting site, is an ideal laboratory to study climate change as it is perched on the edge of the Polar zone and isolated from the effects of human habitation, unlike the densely populated tropics.
They say the rapid animal and vegetation colonisation of Heard Island as glaciers melt is further indicator of the extent of global warming now in the sub-Antarctic.
King penguins numbers have exploded from only three breeding pairs in 1947 to 25,000 in 2001. The fur seal population has recovered from near extinction to now number more than 28,000 adults and 1,000 pups. The island also has a lush green carpet of cushion plants and a member of the rose family is thriving.
"I didn't recognise it," said the Australian Antarctic Division's chief plant scientist Dana Bergstrom, who returned to Heard Island on the expedition after a 14-year absence.
"I was walking across sites that I had previously crawled across. What was barren ground had cushion plants growing over them," she said. "From an Antarctic perspective it is dramatic."
REUTERS NEWS SERVICE