Pronounced Warming of the Greenland Ice Sheet

In the late spring and early summer of 2013, researchers on the SAGE (Sunlight Absorption on the Greenland ice sheet Experiment) Traverse, conducted a 4000 km snowmobile traverse across northwest Greenland. One aspect of this study collected field measurements of borehole temperatures across the northern Greenland ice sheet. Sites first measured by Benson in 1953-1955 are re-visited, showing long term trends in ice sheet temperature. Results indicate a pattern of dramatic warming (up to +5-6 C) at mid-level elevations (1400-2500 m) and little temperature change or perhaps slight cooling at high elevations (>2500 m). Compared to coastal West Greenland stations and Arctic-wide temperature reconstructions, which indicate warming trends of 1-1.5 C over the intervening 58-60 years, both results are surprising. Several mechanisms are explored which may account for the rapid warming of mid-altitude ice sheet, including albedo changes and elevated heat transport into the ice due to percolation. The observed ice warming, increasing ice temperature faster than air temperature changes, has serious implications, potentially driving melt facies up the ice sheet faster than would otherwise be expected and priming the ice sheet for greater runoff production.