Antárctica

As mais recentes do comportamento do gelo na Antárctica. O artigo é do Washington Post: scalating Ice Loss Found in Antarctica - washingtonpost.com. Excertos

"Climatic changes appear to be destabilizing vast ice sheets of western
Antarctica that had previously seemed relatively protected from global warming,
researchers reported yesterday, raising the prospect of faster sea-level rise
than current estimates."

"Rignot said the tonnage of yearly ice loss in
Antarctica is approaching that of Greenland, where ice sheets are known to be melting rapidly in
some parts and where ancient glaciers have been in retreat. He said the change
in Antarctica could become considerably more dramatic because the continent's
western shelf, an expanse of ice and snow roughly the size of Texas, is largely below sea level and has broad and flat expanses
of ice that could move quickly. Much of Greenland's ice flows through relatively
narrow valleys in mountainous terrain, which slows its motion.
The new
finding comes days after the head of the Intergovernmental Panel on Climate Change said the group's next
report should look at the "frightening" possibility that ice sheets in Greenland
and Antarctica could melt rapidly at the same time."

"In all, snowfall
and ice loss in East Antarctica have about equaled out over the past 10 years,
leaving that part of the continent unchanged in terms of total ice. But in West
Antarctica, the ice loss has increased by 59 percent over the past decade to
about 132 billion metric tons a year, while the yearly loss along the peninsula
has increased by 140 percent to 60 billion metric tons. Because the ice being
lost is generally near the bottom of glaciers, the glacier moves faster into the
water and thins further, as a result. Rignot said there has been evidence of ice
loss going back as far as 40 years. "

"The new findings come as the
Arctic is losing ice at a dramatic rate and glaciers are in retreat across the
planet. At a recent annual meeting of the American Geophysical Union, Ohio State University professor Lonnie Thompson delivered a
keynote lecture that described a significant speed-up in the melting of
high-altitude glaciers in tropical regions, including Peru, Tibet and Mount Kilimanjaro in Kenya. "