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Newsweek

April 28, 1975 Studies


The Cooling World

There are ominous signs that the Earth's weather patterns have begun to
change dramatically and that these changes may portend a drastic decline in
food production- with serious political implications for just about every
nation on Earth. The drop in food output could begin quite soon, perhaps
only 10 years from now. The regions destined to feel its impact are the
great wheat-producing lands of Canada and the U.S.S.R. in the North, along
with a number of marginally self-sufficient tropical areas - parts of India,
Pakistan, Bangladesh, Indochina and Indonesia - where the growing season is
dependent upon the rains brought by the monsoon.

The evidence in support of these predictions has now begun to accumulate
so massively that meteorologists are hard-pressed to keep up with it. In
England, farmers have seen their growing season decline by about two weeks
since 1950, with a resultant overall loss in grain production estimated at
up to 100,000 tons annually. During the same time, the average temperature
around the equator has risen by a fraction of a degree - a fraction that in
some areas can mean drought and desolation. Last April, in the most
devastating outbreak of tornadoes ever recorded, 148 twisters killed more
than 300 people and caused half a billion dollars' worth of damage in 13
U.S. states.

To scientists, these seemingly disparate incidents represent the advance
signs of fundamental changes in the world's weather. Meteorologists disagree
about the cause and extent of the trend, as well as over its specific impact
on local weather conditions. But they are almost unanimous in the view that
the trend will reduce agricultural productivity for the rest of the century.
If the climatic change is as profound as some of the pessimists fear, the
resulting famines could be catastrophic. "A major climatic change would
force economic and social adjustments on a worldwide scale," warns a recent
report by the National Academy of Sciences, "because the global patterns of
food production and population that have evolved are implicitly dependent on
the climate of the present century."

A survey completed last year by Dr. Murray Mitchell of the National
Oceanic and Atmospheric Administration reveals a drop of half a degree in
average ground temperatures in the Northern Hemisphere between 1945 and
1968. According to George Kukla of Columbia University, satellite photos
indicated a sudden, large increase in Northern Hemisphere snow cover in the
winter of 1971-72. And a study released last month by two NOAA scientists
notes that the amount of sunshine reaching the ground in the continental
U.S. diminished by 1.3% between 1964 and 1972.

To the layman, the relatively small changes in temperature and sunshine
can be highly misleading. Reid Bryson of the University of Wisconsin points
out that the Earth's average temperature during the great Ice Ages was only
about seven degrees lower than during its warmest eras - and that the
present decline has taken the planet about a sixth of the way toward the Ice
Age average. Others regard the cooling as a reversion to the "little ice
age" conditions that brought bitter winters to much of Europe and northern
America between 1600 and 1900 - years when the Thames used to freeze so
solidly that Londoners roasted oxen on the ice and when iceboats sailed the
Hudson River almost as far south as New York City.

Just what causes the onset of major and minor ice ages remains a mystery.
"Our knowledge of the mechanisms of climatic change is at least as
fragmentary as our data," concedes the National Academy of Sciences report.
"Not only are the basic scientific questions largely unanswered, but in many
cases we do not yet know enough to pose the key questions."

Meteorologists think that they can forecast the short-term results of the
return to the norm of the last century. They begin by noting the slight drop
in overall temperature that produces large numbers of pressure centers in
the upper atmosphere. These break up the smooth flow of westerly winds over
temperate areas. The stagnant air produced in this way causes an increase in
extremes of local weather such as droughts, floods, extended dry spells,
long freezes, delayed monsoons and even local temperature increases - all of
which have a direct impact on food supplies.

"The world's food-producing system," warns Dr. James D. McQuigg of NOAA's
Center for Climatic and Environmental Assessment, "is much more sensitive to
the weather variable than it was even five years ago." Furthermore, the
growth of world population and creation of new national boundaries make it
impossible for starving peoples to migrate from their devastated fields, as
they did during past famines.

Climatologists are pessimistic that political leaders will take any
positive action to compensate for the climatic change, or even to allay its
effects. They concede that some of the more spectacular solutions proposed,
such as melting the Arctic ice cap by covering it with black soot or
diverting arctic rivers, might create problems far greater than those they
solve. But the scientists see few signs that government leaders anywhere are
even prepared to take the simple measures of stockpiling food or of
introducing the variables of climatic uncertainty into economic projections
of future food supplies. The longer the planners delay, the more difficult
will they find it to cope with climatic change once the results become grim
reality.