photo: US Geological Survey via flickr
Two pieces on Arctic ice which are worth paying attention to today: 1) Via Climate Progress, Wieslaw Maslowski of the Naval Postgraduate School has presented some new research showing how autumn in the Arctic is likely to be ice-free by the end of this decade and perhaps much sooner--either option is well ahead of the 2007 IPCC report projections; and, 2) In case you had any doubt about melting ice in the Arctic, a team of scientists led by Leonid Polyak from Ohio State University have re-examined data from past on ongoing studies and have found that Arctic ice cover is at the lowest point for at least several thousand years. Both Ice Extent & Volume Shrinking Rapidly
Polyak's team looked at data from nearly 300 studies, combining them to form what they are calling the first "comprehensive history of Arctic ice." Polyak describes the ice-loss, which he notes started in the early 20th century and has sped up in the past three decades, "appears to be unmatched over at least the last few thousand years."
Polyak also notes that what they are looking at is the change in extent of ice over time, not thickness--something which is also declining:
Underneath the surface, the ice can be thick or thin. The newest satellite techniques and field observations allow us to see that the volume of ice is shrinking much faster than its area today. The picture is very troubling. We are losing ice very fast.
image: Climate Progress
Some Ice Above Greenland May Survive, But That's It
As for Maslowski's projection about ice-free autumns in the Arctic by 2016 (±3 years), read the original Climate Progress piece if you want the blow-by-blow, but here's take-away (emphasis is mine):
This projection is based on a combined model and data trendline focusing on ice volume. By "ice-free," Maslowski tells me he means more than an 80% drop from the 1979-2000 summer volume baseline of ~200,00 km^3. Some sea ice above Greenland and Eastern Canada may survive into the 2020s (as the inset in his figure shows), but the Arctic as it has been for apparently a million years will be gone.
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More on Global Climate Change:
Arctic Sea Ice Loss Confirmed as Main Cause of Faster Polar Warming
The Clearest 5 Minute Lesson on Arctic Ice Melt You'll Ever Get
China Plans For Ice-Free Arctic Shipping - Would Shorten Trip to European Ports by 4000 Miles