BY . . . GAVIN SOUTER By air mail from New York
Don’t scoff when you hear an old timer say: “Summers are hotter than they used to be.” This remark could once have been classed with “Stairs are steeper than they used to be,” and “Young people are wilder than when I was a boy.”
But today an impressive number of scientists, both old and young, are convinced that the oldtimers are right.
Summers are getting warmer and, despite the unusual temperatures this year along Australia’s east coast, winters generally are not as cold as they used to be.
This climatic fluctuation which began a century ago and has become more noticeable in the last 20 years has been discussed since the nineteen-twenties almost exclusively in scientific circles.
Recently, however, it has become a subject of more than academic interest. Scientists hasten to assure the world that there is no immediate cause for alarm. The change is merely part of the endless cycle of heat and cold which started with the first ice age about one million years before the birth of Christ.
SINCE the turn of this century, meteorologists and their grander associates, the climatologists, have been laboriously gathering evidence of the latest change. The account of these labors from Alaskan glaciers to African lakes is as fascinating as any detective story.
Dr. Hans W. Ahlmann, director of Swedish Geographic Institute, is an authority who has spent most of his life reading these signs. A recent report based on his work shows that the new climate is coming just as surely as winter or summer.
Subzero temperatures occur only half as frequently in northern cities as they did 75 years ago.
Greenland’s ice is melting and the ruins of medieval farm-houses hidden by ice for centuries have already been exposed.
In Spitsbergen the mean annual temperature has risen by four degrees since 1912.
Ships ply the White Sea and Gulf of Bothnia 3 or 4 weeks longer than they used to.
In Iceland and the high- er latitudes of Norway farmers are growing, barley in soil that was once frozen for 7 months each year.
BUT the coming of the new climate is most noticeable above the world’s snow lines.
Glaciers present the most striking evidence. American geographer, F. E. Matthes, has reported that “glaciers in nearly all parts of the world receded regularly during the last 60 years but especially rapidly during the 1930-40 decade.”
All glaciers examined from Greenland through Scandinavia to Europe are shrinking. And the shrinkage is not limited to high latitudes.
Some glaciers in the European Alps have vanished completely.
In East Africa, the glaciers on three high volcanoes, Kilimanjaro, Mt. Kenya and Ruwenzori, have been diminishing since they were first observed in 1880.
The vast Muir Glacier in Alaska’s Glacier Bay has retreated a full 14 miles since 1902.
A young professor at University of Wisconsin in the far north of US, Joseph Hickey, has been watching the birds of his State for the last 10 years and he, too, is convinced that the climate is warming up.
The seas themselves are changing. Sea levels rose when the glaciers of the last ice age began to melt. And now they are rising again.
One geographer reports a general rise throughout the world to the order of one millimetre during the last 30 years. Ahlmann, however, has measured a specific increase of one millimetre each year in the level of waters off Spitsbergen. That distance may be only .039 of one inch, but geographers think it important.
INLAND lakes have fared worse. With no melting glaciers to replenish them, many lakes are slowly disappearing.
Dr. E. Nilsson, of Stockholm University, visited Africa in 1947 and found that the water level in Lake Victoria had fallen 7 feet in the last 10 years.
In America, the Great Salt Lake in Utah has lost nearly 50 p.c. of its volume since 1850. Its salt content has doubled during that time.
These cases of Vanishing Lakes, Shrinking Glaciers and Frightened Birds have now been solved and the sun stands accused.
Dr. L. B. Aldrich, an astrophysicist at Smithsonian Institute, US, published a report this year showing that the sun has poured enough extra heat onto the surface of the earth to affect our climate noticeably.
ALDRICH’S explanation is this: that the radiation of the sun has increased by one quarter of 1 per cent, over the last 20 years.
And this theory is based on 16,000 measurements made in Chile during those years.
Aldrich says that summer is getting warmer all the time. His data has been gathered in recent years by 2 young American university graduates.
These young men spend 2 years in Chile before they are relieved by another pair from US.
At a weather station on Mount Montezuma, high above the Atacama Desert in Northern Chile, these observers have been measuring the unit of the sun’s radiation, the solar constant. Blue enamel skies over this rugged, nitrate desert are clear the year round.
Some scientists may not yet be prepared to agree with Dr Aldrich when he says that the solar constant is rising. But all of them, even the cautious Danes, agree that something is changing our climate.
What effect is this having?
Russia already has good cause to be thankful for that increase of ¼ p.c. Navigation conditions along her northern coasts have improved considerably since the turn of the century.
In 1910 most of the sea lanes were open for only 3 months. Now they are open 8 months each year.
Equally important is the economic benefit derived from increased vegetation in northern latitudes.
Barley cultivation in England has already been extended, while the prospects for agriculture in northern Sweden and Finland have similarly improved.
Dr. Ahlmann has pointed out another effect which the new climate may have. If the Antarctic ice regions and the major Greenland icecap should continue to melt at their present rates, he says, the surface of the ocean may rise to catastrophic proportions.