Sea ice the highs and lows
by Ben Ayliffe
October 18, 2012
There has been aflurryof recent news stories picking up onnew scientific datashowing increased sea ice at the South Pole. This is because the sea ice circling Antarctica reached a record high level late last month, extending 7.51 million square miles, the most ever recorded by satellite.
Meanwhile,climate change skepticsare using this increase to argue that climate change isnt happening after all. Heres what the qualified climate scientists are saying.
Shifts in wind patterns and the giant ozone hole over the Antarctic at this time of year both related to human activity are probably behind the increase in ice. Changes in the strength and motion of winds are now pushing the ice farther north, extending its reach.According to NASA, climate change has created essentially a wall of wind that keeps cool weather stuck in Antarctica.
But sea ice is only a small part of the story in Antarctica. Most of the freshwater held in the region is actually contained within an expanse of ice that covers the land mass and extends into the surrounding ocean – known as the Antarctic ice sheet. Measurements fromsatellitedata since 2002 show that the mass of the Antarctic ice sheet – on land – isdecreasingrapidly and overall, satellite observations show that the Antarctic islosing ice mass.
Sea ice is always melting near one pole while growing around the other. But the overall trend year to year is dramatically less ice in the Arctic and slightly more in the Antarctic.Mark Serreze, director of the snow and ice data center, says computer models have long predicted that Antarctica would not respond as quickly to global warming as other places. Since 1960, the Arctic has warmed the most of the world’s regions, and Antarctica has warmed the least, according to NASA data.
The rapidly melting Arctic ice means more of the black sea is exposed, which reflects less sunlight and absorbs more heat, causing yet more ice to melt. This is what scientists call a positive feedback loop. It is one of many examples of how climate change impacts could themselves cause runaway climate change, meaning the climate is out of control and we cannot bring it under control simply by cutting our emissions.
President Obama himself claimed that “climate change is not a hoax,” and is “a threat to our children’s future.” It’s time both presidential candidates started talking about the most serious long-term issue we all face.