Thursday, July 2, 2015

Arctic Ice Extent: 2015 Struggles For First Place

Fig. 1 (click to enlarge)
The National Snow & Ice Data Center keeps daily track of the Arctic Sea Ice extent/area (NSIDC).

The graph at Fig. 1 shows the current horse race for the lowest sea ice extent/area on record.

It also shows that 2015 was winning the race until about June 13, when the 2015 sea ice extent/area, which had set the record low up until that time this year, slowed down to fall even with the 2012 record for that day of the year (The Question Is: How Much Acceleration Is Involved In SLR - 7?).

Subsequently, on July 1, it seemed to begin to track back toward the 2012 record level.

In this race, we are not talking about quantity / volume of ice, instead, we are talking about how much of the Arctic Ocean the ice covers (How Fifth Graders Calculate Ice Volume, 2, 3, 4).

This extent does not, therefore, have to do directly with sea level rise (SLR), however, since the ice cover is brighter and reflects sunlight, that cover helps to keep the ocean water cool.

On the other hand, when the ice cover mets and is gone, the sunlight enters the blue water, which has a darker albedo, to warm the water more and more.

Which does help to bring on SLR indirectly, since those warmer waters are in currents that travel to eventually flow around Greenland.

That warmth helps to melt the coastal zone ice on the land surface in Greenland.

When that melted ice water reaches the ocean it contributes to SLR  (see this and this).

UPDATE: 2012 is holding the record still (click graph to enlarge):
Fig. 2 (as of July 13)

There are other things to consider, as explained by an Arctic sea ice expert in the video below (and see this).

Dr. Peter Wadhams:

The next post in this series is here.


  1. Here is another Brit who knows the score. (link)

  2. Idly zipping by the mile markers on our way to oblivion.


    1. Thanks to Oil-Qaeda, the "our" in our.