The eleventh domino has fallen.
The extraordinary 2012 Arctic sea ice melt has resulted in a September average sea ice extent of 3.61 million sq km, according to the latest monthly data from the National Snow and Ice Data Center (NSIDC), smashing the previous record of 4.30 million sq km set in 2007.
Today, I’ll quickly review the last month’s progression. I’ll then examine the plausible future course of the Arctic sea ice “death spiral” that is likely to see the Arctic virtually free of sea ice by the 2030s if not sooner, culminating with a new graphic representation of the Arctic sea ice death spiral.
Interest in 2012′s record Arctic sea ice melt has reached the mainstream press both here in Canada (CBC, PostMedia) and abroad (New York Times, Associated Press and the Guardian), now that the Colorado-based National Snow and Ice Data Center (NSIDC) has declared a record low in Arctic sea ice extent.
In my previous discussion of the extraordinary 2012 melt, I noted the eclipse of the old daily record on August 24, three weeks ahead of the 2007 pace. But I also gave a series of short-term projections for the September extent average, which is the metric typically used to track the decline in Arctic sea ice. The 2012 September projection now stands at 3.56 million sq km, slightly down from my previous projection of 3.67 million sq km. That’s more than 700,000 sq km less than the previous 2007 record of 4.30 million sq km.
[UPDATE Aug 24-28: The previous record low for daily Arctic sea ice extent was 4.16 million sq km, set on September 14, 2007. The new record was first set on August 24, 2012 and now stands at 3.85 million sq km. Sea ice extent was reduced by more than 430,000 sq km in five days (Aug 23-27), the most rapid late August loss on record. Click on thumbnail at right for latest Arctic sea ice extent as of today (based on latest NSIDC daily data).
- Aug 22: 4.29 million sq km
- Aug 23: 4.19 million sq km
- Aug 24: 4.09 million sq km ***
- Aug 25: 3.97 million sq km
- Aug 26: 3.94 million sq km
- Aug 27: 3.85 million sq km
*** New record low for daily Arctic sea ice extent set on Aug 24.]
This year’s arctic ice melt season is generating extraordinary interest. 2012′s apparent descent toward a new record low in extent and area is dramatic enough, but it also comes as new analysis shows that summer sea ice loss is 50% more than previously thought in terms of volume, according to preliminary satellite data from CyroSat 2. Virtually ice-free summers in the arctic sea could well arrive by 2030, with troubling implications for accelerated albedo feedback and possibly disruptive changes in the jet stream.
A new record low, eclipsing 2007, does seem increasingly inevitable with each passing week. National Snow and Ice data Center data showed Arctic sea ice extent at 4.29 million square km yesterday, just under 2007′s September average, and a level only reached on September 7 back then. To be sure, 2012 is starting to bottom out, but most years have seen a similar pattern around now.
Here’s a snapshot of the 2012 melt season (with the small crosses denoting recent daily values), compared to the previous five years.
Just how low could 2012 go?