Arctic Report Card

Land

J. Richter-Menge, Topic Editor

ERDC-Cold Regions Research and Engineering Laboratory, Hanover, NH

September 3, 2009

Summary

Observations of land-based changes in the Arctic cover a wide spectrum, including variations and trends in vegetation, permafrost, river discharge, snow cover, and mountain glaciers and ice caps. In general, these observations present further evidence of the impact of a general, Arctic-wide warming trend that is accompanied by high variability from year to year and region to region. For instance, the 2007/08 and 2008/09 snow cover seasons marked a continuation of the trend towards shorter snow seasons due to earlier spring melt, which has been observed during the last two decades following a rapid reduction in snow cover duration that occurred in the 1980's. Despite this overall trend, there was evidence of considerable annual and regional variability. The Arctic 2008 spring melt exhibited close to normal conditions over Eurasia, but the earliest snow cover disappearance in the period of record (1966-present) over North America. In 2008/09, the Arctic snow cover was slightly deeper than average in many areas, and the onset of snow melt was near normal or slightly later than normal across large regions of the Arctic, yet the melt intensity was sufficient to again produce an earlier than usual disappearance of snow.

Other observations reveal that there has been a general increase in land-surface temperatures and in permafrost temperatures during the last several decades throughout the Arctic region. New permafrost data from Russia show striking similarity to observations made in Alaska, with permafrost temperature typically increased by 1 to 2°C in the last 30 to 35 years. Significant losses in the mass of ice sheets and the area of ice shelves continued, with several fjords on the northern coast of Ellesmere Island being ice-free for the first time in 3000-5500 years. There continues to be a general increase of freshwater input to the Arctic Ocean from major rivers in Eurasia and North America.

Illustrating the connectivity between various elements of the Arctic system, direct observations confirm model predictions that the affects of the retreating sea ice influence the temperature and vegetation of adjacent lands. Temporal analyses generally show that, within a specific region, periods of lower sea-ice concentration are correlated with warmer land-surface temperatures and an increase in the amount of live green vegetation in the summer.

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