CO2 emissions pose huge threat to Antarctic ice sheet. Would raise the global sea level by about 60 meters

The world is on track for massive sea level rises resulting from the melting of an Antarctic ice sheet if carbon dioxide emissions continue as predicted, a leading New Zealand expert said Friday.

The melting of the giant East Antarctic ice sheet would raise the global sea level by about 60 meters, Professor Tim Naish, director of Victoria University's Antarctic Research Centre, said in a statement.

Naish took part in an international study that showed the ice sheet would become unstable and melt if carbon dioxide levels in the atmosphere reached 600 parts per million -- a level that might be reached by the end of the century if the world failed to meet emissions reductions targets agreed to in Paris last year.

"It's a sleeping giant," said Naish.

Drill cores showed that the first Antarctic ice sheet had advanced and retreated many times between 34 million and 35 million years ago before finally stabilizing at its largest extent when atmospheric carbon dioxide levels dropped below a threshold of 600 parts per million.

With carbon dioxide levels already at 400 parts per million and predicted to go higher, the study provided valuable insights into the potential future stability of the Antarctic ice sheet.

"We know that parts of the ice sheet sitting below sea-level in West Antarctica are already melting in response to current global warming, but the much larger East Antarctic ice sheet, which sits mostly on rock above sea-level, was thought to be more stable," he said.

"We found it is vulnerable, and was much smaller the last time atmospheric carbon dioxide levels matched those predicted before the end of the century."
[ Xinhua - china.org.cn]
11/3/16