Wind and water currents turn ice into an “ensemble of floes”

By NUNATSIAQ NEWS

New research from the Massachusetts Insitute of Technology says the most recent global climate report “fails to capture trends in Arctic sea-ice thinning and drift,” and in some cases “substantially underestimates these trends.”

The Intergovernmental Panel on Climate Change Fourth Assessment Report, released in 2007, forecast an ice-free Arctic summer by 2100.

But this may happen much earlier, according to research by Pierre Rampal from MIT’s department of Earth, Atmosphere, and Planetary Sciences, says an MIT news release on research to be published in Journal of Geophysical Research – Oceans.

IPCC models focused on changes in temperature, which are one way to lose or gain ice.

But Rampal says wind and ocean currents also batter the ice, causing it to break up.

And ice that’s in small pieces behaves differently than ice in one large mass.

Wind and currents also play a significant role in winter when they can cause “drastic effects” on the ice’s shape and movement.

As today’s Arctic Ocean winter ice cover is thinner, it breaks up more easily under the influence of winds and currents. So, eventually it looks like an “ensemble of floes,” Rampal said, instead of one large mass.

In summer, natural melting due to warmer temperatures opens the door to even more breakup, he said.

However, large cracks in the winter’s ice cover can help create new ice, since the extremely cold air in contact with the liquid ocean promotes refreezing.

This means “it’s hard to predict the future of Arctic sea ice,” admits Rampal, who is working on a project with researchers at MIT and NASA’s Jet Propulsion Laboratory to combine models and observations which will produce a more accurate picture of what’s happening.

Earlier this month, the National Snow and Ice Data Center Arctic sea ice extent in July 2011 broke its previous record low set for that month in 2007.