SHRINKING ICE

Greymouth Evening Star, 20 December 1934, Page 11

SHRINKING ICE

GLACIERS OF SWITZERLAND. Switzerland’s glaciers are shrinking. They have been shrinking ever since 1922, and last year’s figures, recently given but by Professor P. L. Mercanton, director of the Swiss Meteorological Office, indicate that the shrinkage is not only being maintained, but seems to be accelerating, writes Clair Price in the “Daily Mail.” So far as it goes, this tends to confirm glaciologists in their theory that glaciers move in great cycles of alternate advance and retreat extending over periods of, roughly, 35 years each. If this theory is correct, the glaciers of the Alps should continue retreating until 1957, when another great cycle of advance should set in. One might easily assume that it would be a hopeless task to cope with the confusion of; movement which is always at work in the snout of a huge glacier. There would be no snout at all if it were not for the fact that the glacier has descended to an altitude at which it thaws more rapidly than it renews itself. In the winter, when its thaw stops or is greatly retarded, it pushes on down at its rate of an inch, a foot, or a couple of feet a day. In the summer, more rapidly than its rate of advance can renew it, the snout retreats until another winter gives it a chance.

SIMPLE WORK. Always, on top of this ceaseless confusion of movement, there are the great cycles of alternate advance and retreat which the glaciologists are attempting to chart in the theory which they call the Bruckner theory. But to the glaciologist this is simple enough. The end of winter is the time of the maximum seasonal advance, and therefore the moment for the annual measurement to be taken. Professor Mercanton, in the collected 1933 measurements which he has now announced, tells us that the great Allalin glacier, east of the Rimpfischhorn above Zermatt, retreated 30 feet last year. The Fiesch glacier, to the east of the Eggishorn above the Rhone valley, retreated 33 feet. The Trient, the northernmost glacier of the Mont Blanc range, retreated 48 feet, while the Oberaar and Unteraar, in the vast nest of glaciers to the east of the Jungfrau, retreated 93 feet and 162 feet respectively. Of the total of 100 Swiss glaciers which were measured, four were at a. standstill, 15 were advancing, and 81 retreating. Ten years ago the annual measurements indicated that, of thfj same 100, 12 were at a standstill, 22 were advancing, and 66 retreating. The 1933 measurements accordingly fit into the Bruckner theory as nicely as those of ten years ago do, but glaciologists do not yet regard this theory of 35-year cycles of alternate advance and retreat as definitely established. A century of glacier measurements in the Alps seems to support it, but glaciology moves so slowly that it takes more than a mere century to establish a new glacial law. The glaciologists are able to .tell us that the Alpine glaciers had a maximum of advance between 1810 and 1825 and another maximum along towards 1855, after which they all retreated. About 1875 a slight tendency towards advance reappeared, they say, among the glaciers • of the Chamonix region and worked gradually eastward, expiring in the Swiss Alps in 1893 and in the Tyrolean Alps in 1901, Meanwhile, a more marked advance was setting in, and it was not until 1922 that it passed its peak and descended into the present cycle of retreat.