November 30, 1997

Cushioning the Shock of Global Warming

By WILLIAM K. STEVENS

n the debate over global warming, attention has focused mainly on how to reduce emissions of excess carbon dioxide and other heat-trapping industrial waste gases. Negotiators from more than 150 countries will convene Monday in Kyoto, Japan, to try to agree on just such cuts.

But many experts are convinced that whatever action is taken, the world's political and economic systems are probably not capable of responding fast enough to keep carbon dioxide concentrations in the atmosphere from rising, late in the next century, to about twice what they were when fossil fuels began to be spewed into the air during the Industrial Revolution in the late 18th century.

If scientists are correct, floods like this one in Idaho Falls, Idaho, will become more frequent. Credit: Randy Hayes/The Idaho Falls Post-Register

If mainstream scientists are right, a doubling of carbon dioxide would mean that the world is already assured of a substantial rise in global temperatures and sea level, heavier rainstorms, more severe droughts and floods and a poleward shift of climatic zones.

With that realization, the question of how well the world is prepared to adapt to climate change is gaining new attention.

"We are pretty clearly going to be moving into uncharted territory in a world of doubled carbon dioxide concentrations," said Dr. Richard Moss, an expert with the Intergovernmental Panel on Climate Change, an advisory group set up by the United Nations. "Developing and implementing adaptation options seems to be a prudent course at this point."

While some strategies for coping with a different climate might be devised, it would probably not be possible to cushion all shocks. Such measures as building sea walls and planning for more efficient use of water in increasingly drought-prone areas, for instance, would go only so far.

There will surely be winners as well as losers: while Canadian and Russian farmers might reap more wheat, African farmers might reap drought-induced disaster. While summer heat in the southern United States might be more intense, northern winters might be milder. The economies of entire regions -- tourist-dependent New England, for instance -- might be transformed with uncertain results. Adapting to climatic upheaval would surely involve great human and financial cost despite any planned measures.

But humans are a resilient species. They have always had to contend with climatic change and have often been profoundly affected by it. Conventional wisdom now holds that Homo sapiens owes its very existence to a climatic adaptation.

According to this view, the onset of a drier ice-age climate in sub-Saharan Africa some 2.5 million years ago shrank forest cover, expanded grasslands and forced a certain species of pre-human to take up a two-legged life on the ground permanently, setting off an evolutionary chain of events that led directly to modern man.

Much later, experts now believe, a similar drying so constricted natural food supplies in the Middle East that people were forced to begin cultivating grains -- a revolutionary adaptation that transformed human society and touched off a population expansion leading to human dominance of the planet. Still later, mega-droughts in both hemispheres destroyed several early empires that failed to adapt.

In the Little Ice Age of the 15th to the 19th centuries, the inability of humans to adapt to extreme cold led to crop failures, starvation, mass migration and, in some instances, cannibalism. But despite the misery and cost, that same time (which was punctuated by some mild periods) was one of the most creative in history, the era of the late Renaissance, the Enlightenment, the American Revolution and the rise of the industrial economy.

One way to get at the question of how to adapt to global warming is to ask how well modern people already deal with extreme events, like floods and droughts, that are expected to become even more extreme. "The answer is, not well," said Dr. Michael H. Glantz, a social scientist at the National Center for Atmospheric Research in Boulder, Colo., who bases his conclusion on a number of case studies in the United States.

The worst prospects are in developing countries, which in many ways are inherently more vulnerable. Countries like Bangladesh, Egypt, China and many small island countries, for instance, stand to see much or even all of their territory inundated by rising seas.

At the same time, many Third World populations, particularly in drought-prone countries, exist precariously close to the edge. Any increase in the length or severity of droughts could push them over -- and their countries' agriculture-dependent economies as well.

To a great extent, the United States and other rich countries "have managed to insulate ourselves from the vagaries of climate," said Dr. Peter Gleick, the director of the Pacific Institute for Studies in Development, Environment and Security in Oakland, Calif.

For instance, the United States has spent billions on reservoirs, dams, pipelines, aqueducts and irrigation systems that help smooth out the effects of climatic extremes on water supplies and floods. "But people in most developing countries really live with the climate," said Gleick. "If the rains fail, their crops fail. If the rivers flood, often they die."

Similarly, farmers in the United States have at their disposal a wealth of expertise and resources to help them adjust the kinds of crops they grow to cope with a new climate -- albeit at some cost. A farmer in much of Africa or in Bangladesh has nothing comparable.

In North America, global warming would probably bring some benefits. Northern climes are already becoming greener as the world warms, and future warming might expand the continent's agricultural belt. Farmers farther south could switch crops; citrus fruits might replace field crops in Georgia, for example. Milder northern winters could cut the costs of heating and snow removal.

But for every benign impact, according to the intergovernmental panel, there would be at least one negative counterpart.

How will the New England tourist industry adjust, for instance, if brilliant fall foliage is replaced by duller oaks and hickories from farther south and ski slopes turn to slush? How disruptive and expensive would it be to progressively abandon beachfront developments as seas rise? What would be the impact of increased summer demand for air conditioning on power supplies and costs? Are public health agencies ready for an expected increase in heat-related deaths and possibly the migration of tropical diseases farther north?

These questions are just beginning to be asked.

The typical response to climate-related disaster has usually consisted of waiting until something bad happens and then scrambling to cope. Recent examples include the Mississippi River flood of 1993 and the Ohio River and North Dakota floods of 1997. If heavier rains and more severe droughts are in the cards, as the panel predicts, the vulnerability can only increase.

But inertia is a powerful force: even after a big flood like those of the last few years, people continue to tempt fate by living on flood plains even though federal policy now encourages them to move -- with one hand, anyway. With the other, it encourages them to stay by insuring flood damage.

In the end, there is probably only so much that can be done. "I think there are limits to adaptation even in the rich countries," said Gleick. Experts have barely begun to probe what those limits are.

Fifty or 100 years from now, if scientists' predictions about climate change turn out to be right, it may be that people will take the new climatic order in stride. How much pain, strain and cost lie between here and there is anything but certain.