SAN FRANCISCO, CA., DEC. 11, 2013 — Judith Lean spoke with The Yale Forum about her Tuesday lecture at AGU, summarizing her presentation and speaking to her hypothesis that large dips in Arctic summer sea ice are influencing winter temperatures in the Northern Hemisphere, and in turn global average temperatures.

A graph clipped from Lean’s presentation shows the recent winter deviations.

Here the orange line is the expected global average surface temperature from a statistical model that incorporates greenhouse gases, ENSOs, volcanoes, and solar intensity. The white line is the actual observed temperatures, as measured by the Hadley Center’s HadCRUT4 data series, and the blue line is the deviation between the two, with a time lag of 5 months.

Topics: Climate Science, Snow & Ice