Melting of the Greenland Ice Sheet: Short Term Event or Long Term Climate Change?

15 August 2012

A recent post on Wired's Geek Mom blog discusses the latest  satellite info from the scientific community which reveals significant melting on snow and ice on Greenland. Three different satellites have shown that Greenland's surface has gone from approximately 40 percent melted water to approximately 97 percent. Additionally on-the-ground research in Greenland  has verified a warming of surface temperatures that correlate with melt.

The author, Patricia Vollmer, makes the point that while this news is undoubtedly significant in the climate community, there is insufficient data to support the widespread media attention linking these events to climate change and global warming

A few excerpts of Vollmer's arguments:

  • The media is using the term “unprecedented”. In fact, the NASA press release about this is using the term “unprecedented”. What is “unprecedented” about this news is the ability for the satellites to see the warming, and the speed with which that data can be seen by the scientists. The warming itself certainly is not unprecedented. Conditions supporting this were last measured directly in 1889, and ice core samples, which have the ability offer evidence of climate conditions over 100,000 years old, have indicated that vast warming occurs approximately every 150 years. For this to happen in 2012 is not unreasonable.
  • The satellites taking the measurements require some understanding regarding their capabilities and limitations. Greenland is unique in that there is very little else besides rock, ice, snow and water for measurement. So I’m more confident in Greenland’s data than I would be in many other locations. Sand, loam, clay, forests and urban areas can often make detection more difficult. The two satellites mentioned above that measure reflectivities of the land mass surface (Oceansat-2 and SSM/I) are only measuring a few centimeters deep. It essentially measures data that translates into water on the surface. So even if there’s a slight sheen of water for the satellites to sense, there could still be miles of ice directly underneath.  As soon as the temperatures dip below freezing again, it will freeze again.
  • Melting happens on Greenland every year at this time. The melting itself is not what’s unusual. It’s theamount of melting.  Temperatures have been measured as high as 42F this July at locations that rarely exceed freezing temperatures year-round, according to NASA scientist Tom WagnerSome media outlets are coming up with some pretty crazy headlines that might make readers believe Greenland has never experienced melting before.

For Vollmer's full analysis, please read her entire article.