Is Greenland losing ice? (psst, the answer is yes, at an accelerating rate)
by Robert Way, Skeptical Science, September 28, 2010
Confusion caused by anecdotes of structures being buried by accumulating snow on Greenland's ice sheet leads some skeptics to believe Greenland is Gaining Ice. As always, the best way to tease out the truth here by following the research of scientists investigating Greenland's ice mass balance.
In general, the best available science tells us that Greenland is losing ice extensively (Figure 1) and that these losses have drastically increased since the year 2000.
Figure 1. Estimated Greenland Ice Sheet mass balance changes since 1950 using three different methods (Jiang 2010). Mass balance measurement techniques are discussed here.
The evidence suggested by a multitude of different measurement techniques suggests that not only is Greenland losing ice but that these ice losses are accelerating at a rapid pace (Velicogna 2009). Further evidence suggests that although ice losses have up to this point primarily occurred in the South and Southwest portions of Greenland, these losses are now spreading to the Northwest sector of the ice sheet (Khan et al. 2010).
Although there have been some gains at high altitudes, significant ice losses are occurring at low altitudes (Wouters 2008) along the coastline where glaciers are calving ice into the oceans far quicker than ice is being accumulated at the top of the ice sheet (Rignot & Kanagaratnam 2007).
In conclusion, Greenland is losing ice extensively along its margins where fast flowing ice streams are pushing more ice into the ocean than is gained in the center of the ice sheet. For more information on how ice sheets lose mass, a more comprehensive discussion is available here.
Figure 1. Estimated Greenland Ice Sheet mass balance changes since 1950 using three different methods (Jiang 2010). Mass balance measurement techniques are discussed here.
The evidence suggested by a multitude of different measurement techniques suggests that not only is Greenland losing ice but that these ice losses are accelerating at a rapid pace (Velicogna 2009). Further evidence suggests that although ice losses have up to this point primarily occurred in the South and Southwest portions of Greenland, these losses are now spreading to the Northwest sector of the ice sheet (Khan et al. 2010).
Although there have been some gains at high altitudes, significant ice losses are occurring at low altitudes (Wouters 2008) along the coastline where glaciers are calving ice into the oceans far quicker than ice is being accumulated at the top of the ice sheet (Rignot & Kanagaratnam 2007).
In conclusion, Greenland is losing ice extensively along its margins where fast flowing ice streams are pushing more ice into the ocean than is gained in the center of the ice sheet. For more information on how ice sheets lose mass, a more comprehensive discussion is available here.
This post is the Basic version (written by Robert Way) of the skeptic argument "Greenland is gaining ice." Robert has also written a number of richly informative posts on Greenland ice loss. A good starting point is Why do glaciers lose mass. Part two in this series was How do we measure Antarctic ice loss. Part Three responded to disinformation from Steve Goddard about Antarctic ice loss.
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