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Oh my gosh... 2% of the earths surface flooding the planet. Do you know that summer insolation during the early Holocene was 50 W/m2 larger up there than today, totally dwarfing the 1.7 W/m2 addition due to CO2 ? Another hint, did you know that black soot contributes to a significantly higher forcing than CO2 on Arctic ice ? Third hint. Did you know that the worst storms and worst flooding in recorded history occurred during the little ice age and that warmer temperatures have always been beneficial, particularly as they decrease the temperature gradient between Arctic and Tropics ?
Toggle Commented Jun 11, 2014 on The day the ice cap died at Arctic Sea Ice
Thank you for the reply - interesting times. Yes, plenty of historical evidence. I would not call old DMI maps just "anecdotal". Certainly, ice volumes and extents have been lower post 2007 than in the 1930s, however the melt then likely started with more ice and there was less black soot. 1938 resembles 2000 ice extent [link removed] Plus, DMI maps appear to overestimate ice extent, because open sea behind ice barriers could not be detected and untravelled routes typically North of Canada appear to have been assumed ice covered. There is also plenty of evidence for AMO as the main "driver". Temperature data of Greenland may be a good proxy for Arctic sea surface temperatures. The 1940s peak was at about 70% of the recent peak, suggesting AMO contributes 70% to current Greenland warming and similar Arctic ice melt. However, current Greenland temperatures suffer from UHI - Anthony Watts has shown pictures of new Arctic airport temperature sensors (Greenland and Svalbard) which suggest significant UHI due to snow melt around the sensors even in Winter. [links removed] [please, try not to link to proven disinformation websites, can't run the risk of people being misled. Thanks, N.]
Isn't the 2013 melt season just what you would expect from the natural setup ? Record low temperatures due to negative PDO enhanced by low solar activity (+ 3 coldest summers in the last 5 years). Very late melt on the Pacific side as well due to negative PDO. Will we now copy post 1940 ? PDO turned negative in 1940s stopping the melt. Did not refreeze a lot, however, as the data point for 1964 suggests (6.9 mill km2, and 1964 had probably more ice than some earlier years). Big refreeze started only with AMO turning negative. 2 additional questions: 1). Are sea ice levels now so low, that again they can only recover after an AMO switch to negative ? 2). As late 1930s extents are now in the 2000s ballpark, and the 1920-1940 melt likely started with larger sea ice volume, hence may have melted about the same total volume, is there anything exceptional about the 1970s-today melt ?
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Aug 18, 2013