7
April 2009 - An ice bridge linking the Wilkins
ice shelf to two islands in Antarctica has
collapsed, triggering warnings that climate
change is having a clear impact on the region.
A satellite picture
from the European Space Agency (ESA) shows
that a 40 km long strip of ice holding the
Wilkins in place had splintered at its narrowest
point, about 500 meters wide.
The Wilkins shelf, which
is the size of Jamaica, has been retreating
since the 11000s. It is one of many Antarctic
ice shelves that have begun to break up
over the past few decades and it is part
of the Antarctic Peninsula, which has seen
some of the most dramatic temperature increases
in the area - up to 3 degrees, according
to Elaine Baker of UNEP GRID-Arendal's Shelf
Programme.
Christian Lambrechts,
a Policy and Programme Officer with UNEP's
Division of Early Warning and Assessment
(DEWA), warned that the development was
significant: "Although the Wilkins
Ice Bridge collapse will have no direct
consequence on sea level rise, it might
have an indirect impact, as the decay of
the ice shelf will reduce the stability
of the glaciers that are feeding it,"
he said.
"The collapse of
the Ice Bridge will expose a new expanse
of sea surfaces that absorb an increased
amount of solar radiation, contributing
to continued and accelerated warming,"
he added.
According to research
conducted in March 2009 by the World Meteorological
Organization (WMO) for the International
Polar Year (IPY), warming of the Antarctic
is much more widespread than previously
known. The research found that a freshening
of the bottom water near Antarctica is consistent
with increased ice melt from that continent
that could affect ocean circulation.
Indeed, the loss of
the Wilkins ice bridge, jutting about 20
meters out of the water and which was almost
100 km wide in 1950, may now allow ocean
currents to wash away far more of the shelf.
A 2008 report released
by UNEP and the World Glacial Monitoring
Service (WGMS) showed that the average rate
of glacial melting and thinning more than
doubled between the years 2004-2005 and
2005-2006. The estimates, based on measuring
the thickness of glacier ice, indicated
an average loss of around 1.5 metres in
2006, up from just over half a metre in
2005.
