I have previously blogged about the record low (since satellite measurements began) for Arctic sea ice in 2007, and some of the contributory factors, here, here and here. The record high for sea ice coverage in the Antarctic received little or no media attention.
So what is the current situation? NASA’s earth observatory has an Arctic sea ice update here:
“After record retreat in September 2007, Arctic sea ice had been making a slow winter recovery. Mean sea ice extent remained at record-low levels in October 2007, but beginning in late October, sea ice grew by more than 150,000 square kilometers (about 58,000 square miles) per day for about 10 days—the fastest regrowth observed in the satellite record. Despite this rapid growth, sea ice extent remained below normal for November, though it was not a record low.”
According to the University of Illinois website The Cryosphere Today, sea ice coverage for January 31 2008 is about 900,000 square kilometers below average for the Arctic and about 500,000 square kilometers above average for the Antarctic. Compare past Arctic sea ice coverage from 1980 onwards with the present at the same time of the year here.
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Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
See this excellent post at CS for a consideration of the impact of sea ice coverage on albedo:
http://climatesci.org/2008/01/31/current-status-of-arctic-and-antarctic-sea-ice-coverage/
The current above average sea ice coverage in the Antarctic provides a global average negative radiative feedback.
Sea ice thickness is not mentioned.
You’d expect sea ice coverage to recover relatively quickly when there is so much open water – “When summertime ice extent hits a record low, on the other hand, large areas of open water provide room for the ice to grow once temperatures cool off enough”.
Really need to know thickness before you can say anything meaningful about how the ice is recovering
proteus – “The current above average sea ice coverage in the Antarctic provides a global average negative radiative feedback.”
From the reference:
“If the Arctic sea ice areal coverage is again lower this northern hemispheric summer, this would be a global average positive radiative feedback.”
We will wait and see shall we?
“Sea ice thickness is not mentioned”
See – “All About Sea Ice”
http://nsidc.org/seaice/characteristics/difference.html
Ender, I did say the ‘current’…
You would have noticed also the following:
“This feedback is larger also since the Earth is closer to the Sun in January.”
I’m a bit lazy, what is 500,000 sq km and 900,000 sq km in approximate percentage terms?
The raw numbers dont convey much unless you know a bit about sea ice, (which I don’t).
Bill, quite correct, the numbers don’t mean much at all but it’s natural variability and a little more, apparently, than the predictions from the climate models that predict climate states on the planet virtuALGORE