Weasel words about the Antarctic

by Dr. Tom Sheahen

May 22, 2014

Q. On TV I saw that the ice in Antarctica is collapsing, and that will raise sea level and inundate cities. Others reports say this will take thousands of years. How serious is the problem?

What you are witnessing here is a result of confusion between the public perception of the ordinary meaning of words, and the very special definitions used in scientific discourse.

Geologists deal with changes in the earth that occur over epochs of millions of years. Anything that happens in less than 10,000 years is “sudden,” and something happening in only 1,000 years is “instantaneous.” To geologists, the word “collapse” is appropriate for a 10,000 year process.

A hot-topic in the media these days has to do with the West Antarctic Ice Shelf (WAIS), a region comprising about 8% of the ice covering Antarctica. Within that region, there are two glaciers that are sliding down to the sea at a steady pace, as glaciers always do. They comprise about 10% of the WAIS, less than 1% of Antarctic ice. This descent has been in progress for several thousand years, and is neither new nor man-caused. It will go on for a few thousand more, after which they’ll be gone. In the parlance of geology, those two glaciers are collapsing.

If that doesn’t sound to you like your usual meaning of the word “collapse,” you’re absolutely right. It’s a specialized geological term.

Unfortunately, the major media overlook the distinction of meanings, and then make the further generalization from two specific glaciers to the entire WAIS, and moreover to Antarctica in general. Scientists who point out the small actual glacier size (and volume of ice) are brushed aside in the rush to get a headline or a flamboyant sound byte that will keep the viewers tuned in. Words like unavoidable collapse carry a sense of foreboding.

This isn’t just a problem from geology. Confusion over the meaning of words used in science crops up frequently. Laws of physics (e.g., conservation of energy) are said to be true in general, meaning “always true.” But if a physicist says “that is generally true,” a non-scientist hears “that is usually true” – meaning “most of the time, but not always.” Neither is aware of the other’s interpretation.

The word “average” is easily misunderstood. For any set of data, about any topic, you can construct an average. But it may be irrelevant – a good example being the “average temperature of the Earth.” Regional and seasonal variations are so great that a single average number is meaningless. And yet people have such familiarity with the word “average” – batting averages, school grade averages, etc. — that it’s commonplace to believe that any statistic called an “average” represents something real.