Tuesday, March 22, 2011

Decline in Arctic Sea Ice Extent

Arctic sea ice extent has peaked, and it's not especially good news.

According to the JAXA satellite, Arctic sea ice extent peaked on March 8, 2011 at 13.89 M km2.

First, let's note that sea ice extent (akin to area) is not the absolute best measure of Arctic melting. That would be, of course, sea ice volume, which is modeled by PIOMASS.

But PIOMASS relies on modeling and is not a direct measurement, so some purists talk about ice extent.

This year, Arctic sea ice extent was lower than last year, and in fact, lower than any year since 2006:

Here the y-axis is in units of millions of square kilometers.

This is one way to look at the data. Here's another:

Which is best? Don't ask me -- deciding that is your job.


Anonymous said...

Hi David, good to see I'm not the only one calling the sea ice extent maximum. I write regular updates on SIE on the Arctic Sea Ice blog. I've linked to your piece here.

Nicknewf said...

I like your question. Which is best? I would go with a third option at looking at the standard deviations from the 1979 to 2011 norm.

The volume PIOMASS numbers are very distressing.