Arctic Ice Shrinking AND Thinning, says NASA

According to NASA (the National Aeronautics and Space Administration), a dramatic thinning of Arctic ice has taken place over the past five years, with more fragile ice taking over from older, more solid ice.  NASA scientists detailed their findings in a new report issued on July 7th 2009, which added a new layer of concern onto existing scientific knowledge regarding the impact of climate change on the Arctic.  It is now common knowledge that Arctic sea ice has been reducing in size, but the idea of the ice reducing in thickness, too, is a new one.

The relevance of the new findings – ascertained through analysing data provided by satellites – is that thicker ice can withstand summer temperatures, but when this is absent, the seas become more efficient at absorbing the heat that the ice would usually reflect back into the atmosphere.

Arctic Sea Ice Contraction

The NASA scientists employed technology known as ICESat to calculate that the rate of Arctic sea ice contraction stood at approximately seven inches per annum, or just over two feet since 2004.  Their findings were published in the present edition of the Journal of Geophysical Research-Oceans – another one being that – over the same period – there had been a 42 per cent drop in the volume of thicker ice that lasted more than a single summer.

Six years ago, the Arctic’s overall ice mass was comprised of 62 per cent ice capable of enduring multiple summers, and 38 per cent new ice.  Come 2008, this balance had shifted to 32 per cent and 68 per cent, respectively.

“We're losing a lot more of the old ice, and that's significant”, the Jet Propulsion Laboratory’s Ron Kwok told news agency Reuters. “Basically we knew how much the area [of ice] was shrinking, but we didn't know how thick it was.”

ICESat Satellite Imagery

The ICESat satellite imagery took readings across pretty much the entire spectrum of the Arctic region – readings that corresponded favourably with earlier records taken of much smaller areas.

Data from the US National Snow and Ice Data Centre highlights how the overall level of Arctic ice melt reached a near all-time-low during 2008, although this was a slight improvement on the previous year (when it was at its lowest).