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Meit As World Gets Warmer .
Air Mail From New York
DON'T scoff when you
hear an oldtimer 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 to-day an impressive number ot scientists, both old and young, are convinced that the oldtimers are right.
Summers are getting warmer and, despite the unusual tempera tures 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 be- come more noticeable in the last 20 years has been discussed since the ninetecn-lwenties almost ex- clusively in scientific circles.
Recently, however, it has be- come a subject of more than academic interest. The scient- ists 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
There is not yet reason to assume, say the scientists, that the mercury in the world's ther- mometers will now rise any high- er than it would have risen dur- ing two or three other unusually warm periods since the beginning of our calendar. These were not years which scorched the globe as fatally as the ice ages had frozen it. But they were years of mild winters and hard sum- mers. In some parts of Central Europe, Africa and the Ameri- cas they brought drought.
OINCE the turn of this cen
tury, meteorologists and their grander associates, the cli matologists, have been laborious- ly gathering evidence of the latest change. The account of these , labours from Alaskan glaciers lo
African lakes is as fascinating as any detective story.
New seasons come gently with -falling leaves, the glint of hoar , frost and the sort: of birds. New
climates come spectacularly. i Their harbingers are shrinking
glaciers, disappearing lakes ^and the crunching of a moving ice-
Dr. Hans W. Ahlmann, dir- ector of the 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.
Sub-zero temperatures occur only half as frequently in north- ern cities as they did 75 years
Greenland's ice is melting and the ruins of mediaeval farm-
houses hidden by icef' for cen- turies have already been exposed.
In Spitsbergen the mean an- nual temperature has risen by four degrees since 1912.
Ships ply the White Sea and the Gulf of Bothnia three or four weeks longer than they used to.
In Iceland and the higher latitudes of Norway farmers are growing barley in soil that was once frozen for seven 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. The American geo- grapher, F. E. Matthes, has re- ported that "glaciers in nearly all parts of the world receded regu- larly during the last sixty 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 the Uni- versity of Wisconsin in the far north of the United States, Joseph Hickey, has been watch- ing the birds of his State for the last ten years and he. too, is convinced that the climate is warming up.
Comparing his observations with existing records, he says that many species of American
birds and mammals have moved as much as 100 miles northward over the last 40 years. The Tit
mouse, the Turkey Vulture, the Whip-poor-will, the Swallow and
the Opossum have detected the ' change in the climate much more quickly than we have and have moved north to find their accus tomed climatic environment.
EWEN the fish in the ocean
know about it, too. Ahl mann reports that Eskimos are catching and eating cod, a fish that they never saw before 1900. Julian Huxley has reported that herring and haddock have been moving north off Greenland at 24 miles per year for the last 30
The seas themselves are chang- ing. Sea levels rose when the glaciers of the last ice age began to meit. 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. Ahl mann, however, has measured a specific increase of one milli- metre each year in the level of waters off Spitsbergen. That dis stance may be only .039 of one inch but geographers think it im- portant.
Inland lakes have fared worse. With no melting glaciers to re- plenish 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 seven feet in the last 10 years! In America, the Great Salt Lake in Utah has lost nearly 50 per cent, of its volume since 1850. Its salt content has doubled during that time.
These cases of the Vanishing Lakes, the Shrinking Glaciers, and the Frightened Birds have now been solved and the sun stands accused. Dr. L. B. Ald- rich, an astro-physicist at the Smithsonian Institute in the Unit- ed Stales, 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.
The Danish Royal Geographi- cal Society issued a more con- servative statement. In the
Danes' opinion, "the question of the cause will remain open until sufficiently exact measurements of solar radiation for a longer time are available."
Other scientists, however, feel that Aldrich's data is suffi
ciently detailed to provide an ex- planation for the curious evi- dence of a changing climate which has been gathered.
ALDRICH'S explanation is
this that the radiation of the sun has increased by one quartet of one per cent over the last 20 >ears And this theory is based on 16 000 measurements made in Chile dm ing those years Aldrich says that summer is get- ting warmer all the time His data has been gathered in recent years by two young Amencan university graduates
These young men spend two years in Ch.le before they arc relieved by another pair from the United States At a weather station on Mount Montezuma, high above the Atacama Desert m Northern Chile, these obser- vers 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. Ald- rich when he says that the solar constant is rising. But all of them, even the cautious Danes, agree that something is chang- ing our climate.
VyHAT effect is this having?
Russia already has good cause to be thankful for that in- crease of one quarter of one per cent. 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 three months. Now they are open eight months each year.
Equally important is the eco-_
nomic benefit derived from in-' creased vegetation in northern Latitudes. Barley cultivation in
Iceland has already been extend- ed, while the prospects for agri- culture in northern Sweden and
Finland have similarly improved. Timber is now growing beyond what was once the snow line in northern Scandinavia and Alaska.
Dr. Ahlmann has pointed out another effect which the new climate may have. If the Antarctic ice regions and the major Greenland ice-cap should continue to meit at their present rates, he says, the surface of the ocean may rise lo catastrophic propor- tions. "People living in low- lands along the shores would be inundated," he warns.
In a happier vein, this same scientist adds: "It is the first fluctuation in the endless series ot past and future climatic vari- ations in the history of the earth which we can measure, investi- gate and possibly explain."