Through fall and winter, the ice cover of the Arctic ocean grows in extent and thickness. It retreats and thins the following summer, reaching a minimum in September. This annual cycle affects global climate and weather by its impact on the transfer of heat and moisture between lower and polar latitudes, and between the ocean and atmosphere. There has been a downward trend in the amount of sea ice that is particularly steep for the summer months, however this last summer's record ice loss exceeded that of earlier years by a wide margin. For example, the September mean extent was about 25% below last year's minimum extent, about 50% lower than typical ice extent during the 1950s, and five standard deviations outside the 1979-2000 average. The Northwest Passage was open for about a two week period, renewing interest in using the passage commercially.

The talk will discuss the causes behind the extreme minimum extent, and touch on potential implications for those living in the North and at lower latitudes.