Arctic Ice Volume: Definitely Not Good News

Update/correction: I got the units wrong on the graph in the initial version of this post. They’re km³, and I’ve made corrections below. Thanks to Mark Shapiro for catching that.

It’s that time of year again, when those of us in the Northern Hemisphere are immersed in the wonders of Spring and a young man’s fancy turns to… wondering what Neven has posted lately on the Arctic ice conditions. Neven, of course, if the proprietor of the must-read site Arctic Sea Ice Blog. His latest post contains one of those graphs that triggers a “that can’t possibly be right” knee jerk reaction, at least in anyone who isn’t a flaming misanthrope:

This graph shows Arctic sea ice volume (not area, not extent) by month, over the course of the satellite record, with the vertical axis units being km³. (See the link above for more detail on the source of data used in the graph. I also recommend Neven’s post Trends in Arctic Sea Ice Volume.)

Notice that not only is there, shall we say, a distinctly noticeable downward trend, but that the decline for any given month is actually accelerating. Also notice that the vertical axis begins at 0, so there’s no funny business happening here to make the image look even scarier.

The month with the lowest volume, September, has declined from roughly 18,000 km³ to around 4,000 km³. I’ll leave it up to you, dear readers, to conjure up your own way to visualize the volume or weight of that missing 14,000 km³ of ice. (Remember that 1 km³ of ice weighs 1 billion metric tons.) Presumably there are two main factors at work here: Increasing warming due to our continued, non-stop efforts to aerosolize every last gram of carbon we can rip or pump out of the ground, plus Arctic amplification, a.k.a. albedo flip, in which open sea water absorbs much more heat from the sun than would snow and ice.

Of course, the thing that many of you immediately looked for is none of the above details, but when the September line is projected to hit 0, roughly 2015.

This is the part where we all try to resist the urge to say, “that can’t possibly be right”.