artic

Arctic sea ice extent now at record low levels

Satellite observations began in 1979. In the graph above, the dark line is the average summer extent for the period 1979 – 2000. The gray area around it is the measurement uncertainty (2σ if you want to be exact). The dashed green line is the extent for 2007 – the previous record low year – and the blue line is 2012. I added the red line so you can compare 2007 to now. The data numbers show the record is broken, though on the graph they look tied. [UPDATE: The new plot made by the NSIDC for August 26 clearly shows the extent is now lower than the lowest point in 2007.]

As you can see, we’re still on the way down, weeks ahead of the date of the lowest extent in 2007. The minimum extent in 2007 was reached on September 16. In 2011 – which had the second-lowest extent on record, essentially equaling that of 2007 – lowest extent happened on September 9. This year it was August 25.

Notice any trend there? I don’t want to make too much of the idea that it’s happening earlier every year because there aren’t enough data points, but it’s consistent with the Earth’s temperature increasing. The massive heat wave that melted so much ice in Greenland this summer may have something to do with this as well.

Read more: http://blogs.discovermagazine.com/badastronomy/2012/08/27/arctic-sea-ice-extent-now-at-record-low-levels/