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Commentary: Careful with those warming predictions

This article first appeared in the St. Louis Beacon, Sept. 16, 2009 - Suppose that a journalism class in 1959 had been given an assignment to develop a start-up budget for an independent daily like the Beacon to commence operations 50 years hence. Under the heading of “Equipment," each student would have undoubtedly provided for a generous allotment of typewriters. How could reporters and columnists file their copy without them? The more futuristic members of the class may have anticipated the widespread use of electric models.

“Supplies” would have included paper — lots of paper. Standard letter-sized paper for typing, carbon paper for copies, new-fangled Liquid Paper (a.k.a. White Out) for correcting mistakes, huge rolls of newsprint paper for each edition. How could you publish a newspaper without paper?

Had a prescient soul suggested that none of the above would be necessary because we’d now communicate electronically through machines called computers, he or she would have flunked. The assignment, after all, was to write a practical budget, not a science fiction novel. A line item for mouse pads? Why would a newspaper provide lodging for rodents?

I mention all this to illustrate a common short-coming of prediction — namely, the tendency to project a sort of suped-up version of the present forward in time and to mistake that vision for the future. Confined by the parameters of the known, forecasters often remain oblivious to the quiet revolutions taking place around us. From Gutenberg to Gates, the world has been transformed by largely unanticipated developments.

Last March, there was near unanimity among baseball pundits that the St. Louis Cardinals would finish third or fourth in the NL Central. As of this writing, the team is a dead mortal lock to win its division, enjoying nearly insurmountable leads over its projected superiors while vying for the best record in the entire National League.

What happened? The team performed better than expected in the season’s first half, consistently hovering at or near the top of the division—but the race was close. Key mid-season player acquisitions transformed a scrappy group of over-achievers with one bona fide superstar into a collection of thoroughbreds who proceeded to gallop away from their rivals down the stretch. How could you have anticipated these vital personnel moves last winter?

The Sept. 13 Post-Dispatch contained an op-ed piece by Peter Raven, president of the Missouri Botanical Garden. Entitled “Why We Can’t Wait,” the column argues that human-induced climate change has reached critical proportions and that urgent action is needed to avert catastrophe.

It also makes a rather interesting prediction that, for purposes of accuracy, I will quote verbatim: “If all the polar ice melted, which would not occur for many decades after the close of this century, sea level would eventually rise by about 170 feet!” This is the kind of assertion that sounds like hard science at first blush, but upon further review is revealed to be fanciful myth.

The northern polar ice cap floats in the Arctic Ocean like a giant ice cube at the top of the world. In fact, during the Cold War, we used to park Polaris submarines beneath it in the event of nuclear war with the Soviet Union. Likewise, the huge ice shelves off the coast of Antarctica are already in the water.

All this sea ice could melt tomorrow morning and you’d never notice the difference in ocean levels.

To see why this is so, perform this simple experiment in the comfort of your own kitchen: Place several ice cubes in a glass, fill the glass to the brim with water then allow the ice to melt at room temperature. Does the glass overflow? Of course not. Condensation forms on the glass’s exterior but that’s due to the temperature contrast between the interior fluid and the exterior air, which has nothing to do with the water level in the glass.

The reason the glass doesn’t overflow is that frozen water displaces more volume (takes up more space) than its liquid counterpart. This phenomenon explains why un-protected exterior water pipes will burst in the winter if they’re not drained. The water within them expands as it freezes, causing the pipe to fail at its weakest point.

If all the floating ice were to melt, the small fraction that is above the surface would melt into the ocean but the 90 percent or so that is submerged would take up less space. The net effect should be — well — a wash.

But what of the ice on land? Antarctica proper, Greenland, the northern reaches of Alaska, Canada and Russia are all covered by glacial ice. If those masses were to melt, the resulting moisture could raise sea levels — if it found its way to the ocean.

Remember Raven’s time-frame is “many decades after the close of this century.” We’re thus talking 140-150 years from now at the earliest. As glaciers grow and recede at a literally glacial pace, the process would be gradual. Most of the water from the melting ice should be absorbed by the earth beneath it or evaporate into the air — just as the snow in your backyard does when spring arrives.

While the predicted 170-foot flood is unlikely in the extreme, the stated rationale for it is simply wrong. Raven cites data from the environmental advocacy group, Worldwatch Institute, to the effect that “10 of the last 13 years have been the warmest ever recorded.” I don’t know where Worldwatch got its data, but it wasn’t from the contiguous United States.

According to the National Oceanic and Atmospheric Administration , the warmest decade in 20th century American was the 1930s and 6 of the 10 warmest years occurred 1991 or before. The long-term mean temperature in the lower 48 states is 52.8 degrees Fahreheit. The mean temperature in 2008 was 53 degrees Fahrenheit--two-tenths of 1 degree warmer than 1896.

Thus far, 2009 has been even cooler.

He also cites carbon dioxide as “the most abundant” of the greenhouse gases. By far the most plentiful — and effective — heat-trapping atmospheric gas is water vapor. That’s why tropical nights tend to be balmy while desert nights are often quite cold. The moist air of the tropics holds the day’s heat; the dry air of the desert allows it to dissipate into space.

As I said at the outset, predicting the future is always a dicey business. It's even more so when the data used misrepresents the present.

M.W. Guzy is a retired St. Louis cop who currently works for the city Sheriff's Department. His column appears weekly in the Beacon.