Yet More Evidence of Climate Change

An article at ScienceDaily summarizes a new research report by Lindsay and Schweiger (2015) showing that arctic sea ice is vanishing at an alarming rate. Between 1975 and 2012, what ice was present in the arctic thinned by a remarkable 65 percent. This report really ought to put to rest any doubts about whether global climate change is happening.

The study was based on U.S. Navy submarine observations from the Cold War era, as well as later aircraft and satellite measurements.  I have not yet read the journal article, so I cannot comment about whether the authors adequately controlled for disparities in sensor characteristics over that fairly long time span. I assume that they know what they're doing.

Of course, that the arctic is losing ice cover is not news. This is just new, experimental confirmation of what the National Snow and Ice Data Center has been saying consistently for years. Here's their plot (NSIDC, 2015a) of the past five years of sea ice extent for the colder months of the year. All five years' figures are significantly lower than the thirty-year average, indicating that the sea ice is declining.

And here's the NSIDC (2015b) time series plot of sea ice extent for the month of February over a thirty year period, again showing quite clearly that the arctic is losing ice.

You may wonder why this is important. That would be because of the unique and wonderful properties of water. When it's liquid, it soaks up a lot of solar radiation, warming the water and the air above it. But, when it's solid snow or ice, it reflects nearly all of the solar radiation that hits it. So we get a positive feedback effect: A little warming causes a little loss of ice, which causes more warming, which causes more ice loss, and so on. The arctic and antarctic regions thus lead the way in the global climate change that is now very firmly in progress.


References:

Lindsay, R., & Schweiger, A. (2015). Arctic sea ice thickness loss determined using subsurface, aircraft, and satellite observations. The Cryosphere, 9(1) 269-283, doi:10.5194/tc-9-269-2015

National Sea Ice Data Center. (2015a). Arctic sea ice extent [Image]. Retrieved March 6, 2015, from http://nsidc.org/arcticseaicenews/files/2015/03/Figure2-350x280.png

National Sea Ice Data Center. (2015b). Average monthly arctic sea ice extent, February 1979 - 2015 [Image]. Retrieved March 6, 2015, from http://nsidc.org/arcticseaicenews/files/2015/03/Figure3-350x270.png