Newly processed sea ice data, produced under this projectin collaboration with the U.K. Met Office’s Hadley Centre, allow us for the first time to reliably compare recent and early 20th century sea ice retreat. The analysis focusses on these questions:
- What is the response to warming of sea ice and precipitation, as both are expected to respond to temperature?
- Can differences in the sea ice response to recent and early 20th century warming, which appear to be substantial (Burrige, 2009), be explained by different dynamics, and differences in the seasonal and geographic distribution of warming (Ogi et al., 2010)?
- What is the expected response to early 20 century forcing on Arctic sea ice and precipitation, and is there evidence for such changes in observations?
Thus, much improved sea ice data for the early 20th century, and new and expanded precipitation datasets shed new light on the question why observed recent precipitation changes (Zhang et al., 2007) and sea ice changes are surprisingly large (Bitz et al., 2005).