The World's Climate: Unpredictable

Everybody talks about the weather, but nobody can do much about it even today. Short-range forecasting has improved enormously in recent years, even though squalls occur on days when the weatherman insists the precipitation probability is near zero. And despite great advances in techniques and technology, the discipline of climatology--the study of long-range trends in weather--is still an inexact science, to say the least. Climatologists still disagree on whether earth's long-range outlook is another ice age, which could bring mass starvation and fuel shortages, or a warming trend, which could melt the polar icecaps and flood coastal cities.

In fact, scientists have been unable to explain the basic causes of the bizarre weather that afflicted much of the world this summer. Record rains and floods soaked some areas, while droughts parched others, with potentially serious social, economic and political effects. Some examples:

WESTERN EUROPE has recorded one of the hottest, dryest summers in a century. City dwellers have sweltered through abnormally hot days. Farmers in England, northern France, Belgium, northern Italy and West Germany went months without rain, while their fields dried out and their crops shriveled. "My potatoes that should be fist-sized are as big as my thumb," complained a farmer near the small Bavarian village of Hersbruck. "That's what this cursed weather has done." The drought has also turned what promised to be a record British grain harvest into a disaster, lowering harvest expectations from 17.5 million tons to an anticipated 13.8 million. The grain shortage, in turn, is expected to drive the price of animal feed up by some 20%, thus raising the price of beef. Agricultural losses in Germany could be as much as $2 billion.

The prolonged dry spell has also affected transportation. The levels of some German rivers and French canals have dropped so low that barges are carrying reduced loads in order to ride higher in the water. It has also hit hard at the Continent's power systems. With many rivers flowing at only a third of their normal volume and hydroelectric output cut, French utilities have had to burn some 2 million extra tons of oil to meet customer demands for power. As the drought continued in Yugoslavia, Czechoslovakia and Hungary, rains began to fall in Western Europe--too little and too late to be of much help.

AFRICA has been struck by localized droughts in Tanzania, Kenya and in the northern parts of heavily populated Nigeria and Ghana. Near normal rains in the Sahel--the southern edge of the Sahara, where as many as half a million died in the great 1972-74 drought--have brought adequate harvests, but the moisture may prove to be a mixed blessing. The rainfall spawned an almost biblical plague of rats, locusts and caterpillars in Mali, Senegal, Mauritania and Upper Volta. Millions of gerbils, which U.S. children often keep as pets, are loose on the land in Niger, devouring everything in sight.

ASIA, on the other hand, has seen the return of the monsoons in much of India, Pakistan and Bangladesh, which is moving toward self-sufficiency in food production. Bumper rice crops are expected in Thailand and Taiwan this year.

AUSTRALIA has been hit by drought in parts of its southern regions that have had no more than 10% of their normal rainfall this year. Only about half of a planned 24 million acres has been planted with wheat; fodder for cattle is so scarce that farmers are slaughtering livestock they can no longer feed. In Victoria, the air echoes with the sound of gunshots as ranchers, who have already shot about 27,000 head of cattle, rid themselves of stock. In South Australia, stockmen are demanding compensation for an estimated 100,000 head of cattle and 2 million sheep they say must be killed to prevent overgrazing of the barren land.

THE UNITED STATES has also been hit by drought. In California, forests and canyons are tinder dry, and the fire danger is high. Reservoirs in Colorado are down. Drought-caused crop losses in Wisconsin are estimated at $400 million. Despite drought in some areas, however, American growers are expected to harvest more than 2 billion bu. of wheat.

In attempting to explain some of the recent worldwide weather aberrations, meteorologists have traced Europe's grueling hot spell to two strong high-pressure zones, one centered over the Azores, the other just northeast of Iceland. For some unknown reason, the two came together to create the "Azores bridge." This in turn formed what weather experts called the "omega block," a high-pressure barricade that prevented the normal clockwise movement of damp air from the Atlantic to Europe, a flow that usually assumes a vast omega (W*) shape. Australian meteorologists have attributed the drought to the unexplained absence of the rain-bearing westerly winds that usually sweep across the lower part of the continent at this time of year. The dry spells suffered by the U.S. plains states are blamed on blocking by a high pressure center over the upper Midwest.

Cooling Trend. Do all of these abnormalities mean that something is happening to the world's climate? "We know the predictability of weather. We can look at it for two weeks or even 20 days," says Edward S. Epstein, administrator of the National Oceanic and Atmospheric Administration's Office of Environmental Monitoring and Prediction. "But what is the corresponding predictability of climate?"

Climatologists admit that they really do not know. A substantial number believe the earth is undergoing a cooling trend and is returning to the conditions of the "Little Ice Age"--the generally cold, damp weather that prevailed from around 1600 to 1850. British Climatologist Hubert Lamb believes the change is cyclical, occurring every 200 years or so. Reid Bryson of the University of Wisconsin and many others blame the earth's cooling on an increase of dust particles in the atmosphere; the particles act like tiny mirrors, reflecting back some of the sunlight sinking the atmosphere and depriving the earth's surface of solar heat.

There is some evidence that the earth had cooled down--at least temporarily--in the 1950s and 1960s. In 1972, according to German Climatologist Horst Dronia, the atmosphere in the Northern Hemisphere was one full degree centigrade colder than in 1949. But there have been indications of a slight warming since then. If the cooling-theory school is correct, however, the prospects for man are chilling. A global average temperature drop of only 1DEG could shorten the growing seasons in the temperate zones by a critical week or more and reduce food supplies. Increased heating requirements would put a further strain on energy sources.

Other climatologists believe that any long-term cooling trend is being offset by a "greenhouse effect," caused by an increasing atmospheric content of carbon dioxide produced by the burning of fossil fuels. The CO2 prevents some of the heat radiated by the earth's surface from escaping out into space, thus warming the planet's atmosphere. Warming-trend advocates note that winters in such normally chilly regions as Scandinavia and New England have been uncharacteristically mild in recent years, and glaciers in the Alps have actually retreated. Even a modest rise in world temperatures would bring with it other perils. Ocean levels raised by melting polar ice could drastically change global air-circulation and rainfall patterns, as well as cause extensive flooding. The result could be a radical decline in the productivity of many of the world's important agricultural regions.

Climatologists tend to agree that whatever the long-term trend, the earth's climate is entering a period of increased variability that will make prediction and planning ever more difficult. "I do not see glacial melts or an ice age," says Jerome Namias of the Scripps Institution of Oceanography in La Jolla, Calif. "What I see is fluctuations." Stephen Schneider, deputy head of the climate project at the National Center for Atmospheric Research in Boulder, Colo., says the evidence of the past few years suggests that there is a good possibility the climate is becoming more unpredictable.

To learn more about these fluctuations, an international consortium of scientists is compiling a record of the earth's climate. Climatologist Lamb and his colleagues have assembled an accurate historical record of the seasons going back as far as 1400 A.D.--based on parish registers, government documents, monastery records, and such physical evidence as sediment deposits in lakes and growth rings in trees. Says Lamb: "The more we know about cycles of the past, the better we can work with the highly detailed and sophisticated observations we have of our weather today." Geophysicist Willi Dansgaard of the University of Copenhagen is studying cores taken from the ice in Greenland and Antarctica to learn about temperature and precipitation through the ages. Researchers at Columbia University's Lament-Doherty Geological Observatory are examining sea-floor cores for clues to ocean temperatures and circulation.

No Answers. Other scientists are studying the sun to determine if its energy output is constant and if there is any link between sunspots (caused by magnetic storms on the sun's surface) and droughts, which often occur every other time the eleven-year cycle of sunspots reaches its low point. Other investigations--of ocean and atmospheric circulation, the processes of mountain building, the influence of land masses--are all pointed toward a better understanding of global climate. That understanding is sorely needed. "Our knowledge of the mechanisms of climatic change is at least as fragmentary as our data," says a report published last year by the National Academy of Sciences. "Not only are the basic scientific questions largely unanswered, but in many cases we do not know enough to pose the key questions."

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