While this news is very significant in the climatology and glaciology community, some are going step further and are attempting to connect it with other indicators of climate change. The definitive answer to that question is not clear and many news outlets are doing a good job providing a balanced view of this news. Several points should be made about this news:
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 the amount 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 Wagner. Some media outlets are coming up with some pretty crazy headlines that might make readers believe Greenland has never experienced melting before.
Because we have more data than ever before to assess this current melting period, it’s difficult to compare it to the very limited data — point data, if you will — of all the previous melting events. Ice cores and temperature measurements are many kilometers apart.
So I pose the question to the readers: Is this a short-term event, similar to the “derecho” that transited across the eastern Continental U.S. on June 29th, or is this a pointer to long-term climate change? My opinion: we don’t have enough data to make that connection. I’m not debunking the connection, nor am I proclaiming this a symptom of global warming.
What’s your opinion?