Arctic Ice: Midsummer Melt Update
July 23, 2014
Someone pointed me to the amusing tweet by the deranged blogger who goes by the name “Steven Goddard”, fresh from the Heartland Climate Denial conference and feeling his oats apparently, @ Meteorologist Heidi Cullen.
Got me thinking there needs to be an Arctic ice Update. Fortunately Greg Laden has already given us one.
Yup, it’s melting.
As it does every summer, the Arctic Sea ice is melting off. Over the last several years, the amount of sea ice that melts by the time it hits minimum in September has generally been increasing. So, how’s it doing now?
The graph above shows the 1981-2010 average plus or minus two standard deviations. Before going into more detail than that, you should look at the following graphic.
The top chart shows the march of Arctic Sea ice melt for first ten years of the baseline data set only, and the bottom chart shows the last ten years of the same data set. This tells us that the two Standard Deviations for the period 1981-2010 hides an important fact. Since Arctic Sea ice is melting more and more every year, a proper baseline might be the first several years of this period, not the entire period.
Now refer to the graphic at the top of the post. This is the current year’s ice extent. Notice that it is tracking right along the lower edge of the 2 Standard Deviation zone. In other words, the present year is exhibiting what we have been seeing all along: An Arctic with much less ice.
Now look at the years that post date the baseline period, 2011 through the present, including the wildy extreme year of 2012 when a record melt was set.
Here we see that collectively, the last three full years and the present partially documented year exist at the lower end of, or lower than, the 2 Standard Deviation zone. This suggests that the current trend is an extension of the previous couple of decades. More melting on average over time. One would hope this would level off, and maybe it will. But we certainly can not make that claim at this point.