By IANS,
Toronto : With global warming hastening the shrinkage of the Arctic Ocean ice cover, scientists have warned that the North Pole may face ice-free summers as early as 2013.
Further, a US study by two researchers of Indian origin – Geerat Vermeij of University of California at Davis and Peter Roopnarine of the California Academy of Sciences – has predicted that once the Arctic Ocean becomes navigable after 3.5 million years of ice cover, sea creatures from the Pacific Ocean could invade it and subsequently the Atlantic Ocean.
Layers of thicker, multi-year ice have kept the Arctic Ocean frozen for millions of years – whatever ice cover it lost during summer months was recouped during winter months.
But global warming and possibly other factors have hastened meltdown of this thicker, multi-year ice cover.
The summer of 2007 created history when the Arctic Ocean’s ice cover shrank from 14 million square kilometres to just four million.
This summer has proved equally severe on the Arctic ice cover, with Canadian authorities saying that it is seeing an unprecedented meltdown.
If the shrinkage of ice cover continues at this pace, it is feared that the Arctic Ocean may become ice-free during summer months within a few years.
In their study published in the journal Science, Vermeij and Roopnarine claim that global warming is creating similar conditions in the Arctic Ocean that prevailed there during the warm mid-Pliocene period, about 3.5 million years ago.
As a consequence, the warming Arctic Ocean may be invaded by North Pacific sea species which may then proceed into the North Atlantic.
According to Canada’s Alberta University researcher Christian Haas, the sea ice in the region of the North Pole has thinned up to 53 percent between 2001 and 2007.
“The sea ice is becoming more vulnerable to further retreat, as ice thickness is very uniform over large regions, and ice reduction can be very fast once a certain threshold thickness is reached,” he says.
Haas and his team measured Arctic ice thickness for several seasons on a German icebreaker, collecting data using helicopter-borne electromagnetic (EM) instruments.
They found that ice that was 2.5 metre thick in 1991 is now only 0.9 metre thick.
According to Haas, the thinning is a signal of climate change, but he notes it’s still unclear what the underlying mechanisms are.
“The faster ice motion is due to changes in atmospheric circulation patterns. The independent thinning is due to increased oceanic and atmospheric heat fluxes, and it is likely those atmospheric heat fluxes, like higher air temperature and increased infrared radiation, are the major causes.”