Subject: Warming:Antarctic: Warmer temperatures (fwd)

Michael Williamson (
Tue, 18 Feb 1997 11:42:11 -0500 (EST)

Date: Mon, 17 Feb 97 12:48:00 GMT 
Subject: Antarctic: Warmer temperatures

Antarctic: Warmer temperatures change penguin numbers

   By Elisabeth Mealey, through AAP
penguin biologist, who has been researching the effects of climate
change on penguins on the Antarctic Peninsula for
the past 20 years, has added further fuel to his theory that warmer
temperatures are having a marked impact on the ecology of the area.
   In 1992, a team led by Dr Bill Fraser, of Montana State
University in the United States, rocked the Antarctic science
community by debunking the accepted view that increasing numbers of
Chinstrap penguins on the peninsula were due to the reduced
competition for krill from whales, due to whaling.
   Dr Fraser's team claimed that warmer temperatures and reduced
sea ice were the real culprits for the decline in ice-dependent
Adelie penguins and the increase in species which prefer open
water, including Chinstraps.
   With the number of extremely cold winters going from four out of five 50
years ago to just one or two out of five now, the lack of
winter sea ice has been marked.
   Now, Dr Fraser believes that changes in patterns of snow
accumulation and increased cloud cover due to climate change have
also contributed to the extinction of many Adelie penguin colonies
on rocky islands near the United States National Science
Foundation's Palmer Station.
   After analysing the Adelie penguin population decrease on
Litchfield Island between 1975 and 1992, Fraser found that the 12
extinct colonies on the island all had a south-west
aspect where most snow accumulates.
   Warmer winters and reduced sea ice have brought more snow to the
area since sea ice blocks the exchange of water vapour with the
atmosphere. Dr Fraser believes the frequency of
years with open water has led to a gradual increase in snowfall in
the area and a decrease in melting, due to the greater cloud cover.
   Because Adelies nest only on bare ground where neither snow nor
melted snow wateraccumulate, they have been unable to reproduce in
their usual colonies in the past two decades.
   In the period of research at Litchfield Island, 12 colonies -
accounting for almost 60 per cent of the total - became extinct.
   Dr Fraser calls the combination of reduced sea ice and increased
snowfall a "double whammy" for the dwindling Adelie population in
his research area.
   "You've got more snow and less melt and Adelies can no longer,
in some areas, access historical breeding habitat.
   "So the populations are being forced downward," he said.
   A look at other bird and mammal populations in the area also
seems to confirm Dr Fraser's theory that reduced sea ice leads to
an increase in non-ice dependant species.
   Giant Petrels, which prefer open water for fishing, have
increased 100 per cent in the area since 1974 while elephant seals
have increased by 300 per cent and fur seal numbers have
skyrocketed from six breeding pairs in 1975 to 2,000 in 1995.
   For the past three weeks, the Greenpeace ship 'Arctic Sunrise'
has been in the Antarctic Peninsula documenting the impacts of
climate change.