Arctic sea ice past and present
I've previously written about the recent changes in polar sea ice . This post compares the current trends in Arctic ice with the previous century. I've recently read several claims that the recent melting is matched by melting episodes in the 1920s and 1940s. However, those claims are pure bunk. Walsh and Chapman ( 2001 ) compiled records on Arctic sea ice extent since 1870 (updated data available here ). I've graphed their July-September average, together with the July-September average measured by satellites since 1979: