Antarctic Ice Sheet plays pivotal role in climate variability

New Delhi: As per a recent study, the Antarctic Ice Sheet plays a major role in global climate change, say researchers.

The discovery may be a step ahead in explaining why sea ice in the southern hemisphere has been on the rise despite warming of the rest of the Earth.

Global climate models have failed to account for the amount of climate variability captured in the paleoclimate record, said Pepijn Bakker, a former post-doctoral researcher at Oregon State University and now with the MARUM Centre for Marine Environmental Studies at the University of Bremen in Germany.

"One thing we determined right off the bat was that virtually all of the climate models had the Antarctic Ice Sheet as a constant entity," said Bakker, lead author of the study being published this week in the journal Nature.

"It was a static blob of ice, just sitting there. The ice sheet has undergone numerous pulses of variability that have had a cascading effect on the entire climate system."

The research team`s hypothesis was that climate modellers were overlooking one crucial element in the overall system that might affect all parts of the system.

According to Andreas Schmittner, a climate scientist in OSU`s College of Earth, Ocean, and Atmospheric Sciences, the Antarctic Ice Sheet has demonstrated dynamic behaviour over the past 8,000 years.

"There is a natural variability in the deeper part of the ocean adjacent to the Antarctic Ice Sheet -- similar to the Pacific Decadal Oscillation or El Nino/La Nina but on a time scale of centuries -- that causes small but significant changes in temperatures," said Schmittner, a co-author of the study.

"When the ocean temperatures warm, it causes more direct melting of the ice sheet below the surface, and it increases the number of icebergs that calve off the ice sheet."

If the entire Antarctic Ice Sheet were to melt, global sea levels would probably rise some 200 feet or about 60 metres, claim experts.