The Arctic Ice is Melting, but Not As Much as 5,000 – 8,000 years ago, when CO2 was lower.
This diary is my comment to the diary The Ice Is Melting, Really It Is , verbatim, which has been “in moderation” for many hours.
Going back to just 1979 can’t really tell you much about what sort of baseline variation to expect in arctic sea ice coverage. From Large variations in Arctic sea ice
“Our studies show that there have been large fluctuations in the amount of summer sea ice during the last 10,000 years. During the so-called Holocene Climate Optimum, from approximately 8000 to 5000 years ago, when the temperatures were somewhat warmer than today, there was significantly less sea ice in the Arctic Ocean, probably less than 50% of the summer 2007 coverage, which is absolutely lowest on record. Our studies also show that when the ice disappears in one area, it may accumulate in another. We have discovered this by comparing our results with observations from northern Canada. While the amount of sea ice decreased in northern Greenland, it increased in Canada. This is probably due to changes in the prevailing wind systems. This factor has not been sufficiently taken into account when forecasting the imminent disappearance of sea ice in the Arctic Ocean.”
I’d appreciate it if you looked into the ‘state of the art’ of inferring correlations between
1) AMO + PDO vs. surface temperature
2) AMO + PDO vs. arctic ice extent/volume
This has been done, with dramatically high correlation, but is invalid, according to: http://wattsupwiththat.com/2008/01/25/warming-trend-pdo-and-solar-correlate-better-than-co2/
see also Figure 2, a graph of detrended North Pacific Sea Surface Temperature Anomalies and PDO.