August 22, 2012
Arctic Sea Ice Expected To Reach Lowest Point By The End Of The Month
April Flowers for redOrbit.com - Your Universe Online
Sea ice in the Arctic Ocean is likely to hit its lowest next week and then keep on shrinking.
Arctic sea ice extent during the first two weeks of August continues to track below the 2007 record low daily ice extents. As of August 13, ice extent is already among the four lowest summer minimums in satellite record, with five weeks left in the melting season. As of that date, the extent was 483,000 square kilometers below the previous record for the same date in 2007.
Sea ice extent refers to a measurement of the area of Arctic Ocean that contains at least some sea ice. Areas with less than 15% are considered by scientists to mark the ice edge.
"A new daily record ... would be likely by the end of August," Ted Scambos, lead scientist at the data center which monitors ice in the Arctic and elsewhere, told Reuters. "Chances are it will cross the previous record while we're still in sea ice retreat."
This summer could see the ice retreat to less than 1.5 million square miles (4 million square km), an unprecedented low, Scambos said.
Why is Arctic sea ice important to us?
The amount of ice in the Arctic ocean is significant because the region is a potent global weather-maker, sometimes referred to as the world's air conditioner. The bright surface of the ice reflects 80% of the sunlight that hits it back into space, whereas the dark ocean surface would absorb this light and the Arctic Ocean temperature would rise.
This year, the loss suggests a possible opening of the Northwest Passage north of Canada and Alaska and the Northern Sea Route by Europe and Siberia.
This record-breaking low of sea ice extent could signal climate changes. Sea ice melt usually slows down in August as the Northern Hemisphere moves towards fall, but this year it seems to be speeding up. To Scambos, this is a clear sign of climate change spurred on by human activities, most especially the emission of heat-trapping greenhouse gases.
"Everything about this points in the same direction: we've made the Earth warmer," he said.
This summer has also seen unusual melting of the ice sheet covering Greenland, with NASA images showing that for a few days in July, 97 percent of the northern island's surface was thawing. The same month also saw an iceberg twice the size of Manhattan break free from Greenland's Petermann Glacier.
"What you're seeing is more open ocean than you're seeing ice," Scambos said. "It just simply doesn't look like what a polar scientist expects the arctic to look like. It's wide open and the (ice) cap is very small. It's a visceral thing. You look at it and that just doesn't look like the Arctic Ocean anymore."
Seymour Laxon, professor of climate physics at University College London, said he is not surprised by the idea that 2012 will deliver a record low in sea ice extent.
"We got very close to a record minimum last year," he told BBC News. "The fact that Cryosat showed thinner ice last winter, it is not surprising to me that it looks like we will have a record minimum this year."
Cryosat is a radar satellite operated by the European Space Agency (ESA) launched in 2010 to monitor changes in the thickness and shape of polar ice.
The scary thought behind all of this is that scientists have been predicting, based on past data, that the Arctic Sea would be ice free in the summer months by 2100. 2007's record low brought that date forward to somewhere between 2030 and 2040. This year's record-breaking summer might just push that date forward a bit more.