Some Perspective on the Headlining Antarctic Ice Loss Trends

Some Perspective on the Headlining Antarctic Ice Loss Trends From Paul C. "Chip" Knappenberger of Cato. Excerpt:

"The new Sutterley research finds that glaciers in the Amundsen Sea Embayment region along the coast of West Antarctica are speeding up and losing ice. This is potentially important because the ice loss contributes to global sea level rise. The press coverage is aimed to make this sound alarming—“This West Antarctic region sheds a Mount Everest-sized amount of ice every two years, study says” screamed the Washington Post.

Wow! That sounds like a lot. Turns out, it isn’t.

The global oceans are vast. Adding a “Mount Everest-sized amount of ice every two years” to them results in a sea level rise of 0.02 inches per year. But “New Study Finds Antarctic Glaciers Currently Raise Sea Level by Two-Hundredths of an Inch Annually” doesn’t have the same ring to it.

Nor does the coverage draw much attention to the fact that the Amundsen Sea Embayment is but one of a great many watersheds across Antarctica that empty into the sea. A study published in Nature magazine back in 2012 by Matt King and colleagues provided a more comprehensive look at glacier behavior across Antarctica. They did report, in agreement with the Sutterley findings, that glacial loss in the Amundsen Sea Embayment was rapid, but they also reported that for other large areas of Antarctica, ice loss was minimal or even negative (i.e., ice was accumulating). Figure 1, taken from the King paper, presents the broader and more relevant perspective (note that the Amundsen Sea Embayment is made up by the areas labelled 21 and 22 in Figure 1).


Figure 1. Best estimate of rate of ice loss from watershed across Antarctica. The Amundsen Sea Embayment, the focus of the Sutterley study, is encompassed by areas labeled 21 and 22 (taken from King et al., 2012).

We discussed the King and colleagues study in more detail when it first came out. We concluded:

So King and colleagues’ latest refinement puts the Antarctic contribution to global sea level rise at a rate of about one-fifth of a millimeter per year (or in English units, 0.71 inches per century).

Without a significantly large acceleration—and recall the King et al. found none—this is something that we can all live with for a long time to come.

The strategically timed new findings being hyped this week do not change this conclusion."