Warming Permafrost

A pair of articles related to North Slope environmental conditions caught my eye recently, one concerning warming permafrost and the other regarding Dalton Highway construction in response to flooding last spring.  I'll say a few words about the former today and look at the latter in a subsequent post.

In the first article, Vladimir Romanovsky of UAF is quoted as expressing astonishment at rapid rates of warming in permafrost near the Arctic coast, particularly in the last decade.  I'm not familiar with the literature of permafrost studies, so I haven't found published results illustrating the recent trends, but I did find some informative figures at the permafrost database site.  Looking at the "west dock" measurement location at Prudhoe Bay, the following figure shows a striking trend of long-term warming through 2010, and if the professor was accurately quoted, then I'm sure the trend has continued or even accelerated in the past 5 years.

The following chart only extends through 2007, but it shows a similar pattern of significant warming.

A third chart from the database site focuses on temperatures close to the surface, and in this case there is no obvious trend.

I verified the lack of a warming trend in the near-surface temperatures by downloading the daily measurements at 0.85m depth - see below.  The summer peak in temperature at this particular location showed only a very small increase over the decade ending in 2012 (the most recent available).

If we look at air temperature measured near Prudhoe Bay (see below), we see that 2014 and 2015 year-to-date have brought some of the warmest conditions on record, and this may have produced the acceleration in sub-surface warming that the professor seems to be alluding to.  Note that the 1998 spike in temperatures appears to have been responsible for the rapid warming observed between 1998 and 1999 in the first chart above, so it's quite possible that a similar thing has happened again lately.  I'll see if I can obtain some more recent borehole data to document the latest changes.

A note on the chart above: I've combined the climate data from the old Prudhoe Bay observing site (through May 1999) with data from the Deadhorse airport just a few miles to the south (since June 1999).  Deadhorse is a bit colder, being located farther from the moderating influence of the ocean, so the warming trend would actually be a bit steeper if we had observations from the same location over the entire history.  Nevertheless, the temperature drop from 1998 to 1999 was definitely real, as a very similar drop was also observed at Barrow.