Global Warming Feeling the Heat

By MICHAEL D. LEMONICK

For more than a decade, many scientists have warned that cars and factories are spewing enough gases into the atmosphere to heat up the earth in a greenhouse effect that could eventually produce disastrous climate changes. But until recently, the prophets of global warming garnered about as much attention as the religious zealots who insist that Armageddon is near. When Colorado Senator Timothy Wirth held congressional hearings on the greenhouse effect in the fall of 1987, the topic generated no heat at all. "We had a very, very distinguished panel," Wirth recalled at the TIME Environment Conference, "and who was in the cavernous hearing room? Six or seven people, and two or three of them were lost tourists."

So Wirth decided to schedule another hearing in the summer, hoping hot weather would make people pay attention to the greenhouse issue. Sure enough, when the hearing convened last June 23, the thermometer read 99 degrees F, a Washington record for that day. The room was packed when James Hansen, head of NASA's Goddard Institute for Space Studies, turned global warming into front- page news at last. "It is time to stop waffling so much," he declared. "The evidence is pretty strong that the greenhouse effect is here."

Hansen thus became perhaps the most prominent scientist willing to say straight out that the earth-warming effect of excess carbon dioxide (CO2) and other gases generated by industry and agriculture had crossed the line from theory into fact. By itself, Hansen's bold assertion was dramatic enough. But the unusual string of weather-related disasters that struck the world last summer could not have been better timed to drive his point home. The heat waves, droughts, floods and hurricanes may be previews of what could happen with ever increasing frequency if the atmosphere warms 3 degrees F to 8 degrees F by the middle of the next century, as some scientists predict.

On the other hand, the summer's disasters may have had nothing to do with the greenhouse effect. They could have been random events -- all part of the natural year-to-year variations in weather. Many climatologists called Hansen's remarks premature and feared that if this summer happens to be cool, public worries about the greenhouse effect will quickly fade.

Unfortunately, scientists cannot agree on how much global warming has occurred, how much more is on the way and what the climatic consequences will be, giving policymakers an excuse for delay. But no one disputes the fact that the amount of CO2 in the atmosphere has risen and continues to increase rapidly and that the human race is thus conducting a dangerous experiment on an unprecedented scale. The possible consequences are so scary that it is only prudent for governments to slow the buildup of CO2 through preventive measures, from encouraging energy conservation to developing alternatives to fossil fuels.

Some forecasters have suggested that the impact of global warming will not be uniformly bad around the world. After all, Canada would not complain if the productive corn-growing lands of the U.S. Midwest shifted north across the | border, and the Soviet Union might welcome a warmer, more hospitable Siberia. But while the broad outlines of a hotter world are easy to draw, more specific projections are riddled with uncertainty, since the regional weather patterns that would prevail are largely unpredictable. If Canada becomes much dryer than it is now, for example, higher temperatures will not help much.

Moreover, while some nations will probably end up with a more benign climate than they now have, the pace of change could be so jarring that the benefits would be lost. "We're talking about rates of climate change perhaps 100 times faster than at any time in human history," said Stephen Schneider of the National Center for Atmospheric Research. Ecosystems will not be able to adjust so quickly, he said, "and the faster things change, the more likely it is that the impact will be negative." Warned Thomas Lovejoy of the Smithsonian Institution: "There will be no winners in this game of ecological chairs, for it will be fundamentally disruptive and destabilizing, and we can anticipate hordes of environmental refugees dwarfing the numbers of the Dust Bowl era or the boat people."

Ironically, the same greenhouse effect that may be so dislocating made earth hospitable to life in the first place. Without a heat-trapping blanket of naturally occurring CO2, the planet would have an average surface temperature of only 0 degrees F instead of 59 degrees F. Reason: like the glass panes of a greenhouse, CO2 molecules are transparent to visible light, allowing the sun's rays to warm the earth's surface. But when the surface gives off its excess heat, it does so not with visible light but with infrared radiation. And since CO2 absorbs infrared rays, some of the excess heat stays in the atmosphere rather than escaping into space. How much heat is retained depends on how much CO2 is in the air.

Recent research has confirmed that this is more than just theory. By drilling deep into Antarctic and Arctic ice, scientists have been able to measure the amount of CO2 in air bubbles trapped in ancient layers of snow. They have also looked at fossilized plant tissues for clues as to how warm the air was during the same period. The conclusion: CO2 levels and global temperatures have risen and fallen together, over tens of thousands of years. And there is evidence from space: Mars, which has little CO2 in its atmosphere, has a surface temperature that reaches -24 degrees F at best, while Venus, with lots of CO2, is a hellish 850 degrees F.

The ebb and flow of CO2 on earth was caused by only natural processes until less than 200 years ago. With the arrival of the Industrial Revolution in the early 1800s, man suddenly threw a new factor into the climatic equation. Carbon dioxide is released in large quantities when wood and such fossil fuels as coal, oil and natural gas are burned. As society industrialized, coal- burning factories began releasing CO2 faster than plants and oceans, which absorb the gas, could handle it. In the early 1900s, people began burning oil and gas at prodigious rates. And increasing population led to the widespread cutting of trees in less developed countries. These trees are no longer available to soak up excess CO2, and whether they are burned or left to rot, they instead release the gas. By the late 1800s atmospheric CO2 had risen to between 280 and 290 parts per million. Today it stands at 350 p.p.m., and by 2050 it could reach 500 to 700 p.p.m., higher than it has been in millions of years.

But carbon dioxide, once thought to be exclusively responsible for the greenhouse effect, is now known to cause only half the problem. The rest comes from other gases. Chlorofluorocarbons, or CFCs, are not only destroyers of the stratosphere's ozone layer but powerful greenhouse gases as well. So are nitrogen oxides, which are pollutants spewed out of automobile exhausts and power-plant smokestacks. Another greenhouse gas is methane, the primary component of natural gas. Methane is also generated by bacteria living in the guts of cattle and termites, the muck of rice paddies and the rotting garbage in landfills. Each of these sources is fostered by human activity -- even the termites, which thrive in the clearings left after tropical rain forests are cut down. Humanity's contribution to the greenhouse effect comes from so many basic activities that man cannot realistically expect to stop the process, only slow it down.

A first step toward doing that is to ban the production of CFCs, which are used to make plastic foam and as coolants in refrigerators and air conditioners. These gases account for an estimated 15% of the greenhouse effect. Another strategy is to burn as much methane as possible. That adds CO2 to the air, but getting rid of the methane is well worth it. Both gases trap heat, but as a greenhouse gas, methane traps 20 times as much heat as carbon dioxide, molecule for molecule.

Methane from cattle feedlots will be very difficult to collect, but the gas in garbage landfills is already being tapped and burned at many sites around the U.S. At the Fresh Kills landfill on New York City's Staten Island, for example, methane that would otherwise have escaped into the air is being collected by a gas company and used to heat thousands of homes. The technique essentially involves driving a pipe into the depths of the garbage, then trapping the gas that rushes out. This should be done at all landfills.

Another step that could be taken to counteract global warming is to slow -- and ideally stop -- deforestation. But that is an enormously complex task, and so a simple companion strategy should be adopted at the same time: the planting of trees, and plenty of them, to absorb CO2 from the air. "It surely has to be one of the most benign things we can do," said Gus Speth of the World Resources Institute. Tree planting can be encouraged at all levels of society, from individuals putting an extra tree or two in their backyards to local communities and private organizations planting an acre at a time to provincial and national governments reforesting on a more widespread basis.

Admittedly, trees are just a stopgap. Unless a tree is used for lumber, it eventually dies and rots or is burned, releasing whatever CO2 it has absorbed. But since the rapid pace of change may be the greatest danger posed by global warming, stopgaps could be important. If nothing else, reforestation will buy time to put other preventive measures into place.

Tree planting will have negligible impact, however, if people continue to pump CO2 into the atmosphere at current rates. While wood and fossil-fuel burning will never be eliminated, they can be cut down significantly. An immediate way to do so is through conservation. When oil prices soared in the 1970s, industries responded by becoming much more energy efficient. But the plunge in the price of oil from $36 per bbl. in 1982 to less than $12 per bbl. this fall has cooled the enthusiasm for conservation. Governments must rekindle that interest and boost energy saving by setting or raising minimum efficiency standards for automobiles, appliances and other machinery.

Although developed countries waste the most energy, there are plenty of opportunities for conservation in the developing world, where energy-using equipment tends to be older and more inefficient. Third World conservation would not only help slow greenhouse warming but also let countries save money | by reducing dependence on energy imports. If the industrialized countries expect cooperation, though, they should make available at minimal cost the most advanced energy-saving technology, especially for power plants, and help finance the purchase.

By far the most efficient and effective way to spur conservation is to raise the cost of fossil fuels. Current prices fail to reflect the very real environmental costs of pumping carbon dioxide into the air. The answer is a tax on CO2 emissions -- or a CO2 user fee, if that is a more palatable term. The fee need not raise a country's overall tax burden; it could be offset by reductions in income taxes or other levies.

Imposing a CO2 fee would not be as difficult as it sounds. It is easy to quantify how much CO2 comes from burning a gallon of gasoline, a ton of coal or a cubic yard of natural gas. Most countries already have gasoline taxes; similar fees, set according to the amount of CO2 produced, could be put on all fossil-fuel sources. At the same time, companies could be given credits against their CO2 taxes if they planted trees to take some of the CO2 out of the air.

A user fee would have benefits beyond forcing a cutback in CO2 emissions. The fuels that generate carbon dioxide also generate other pollutants, like soot, along with nitrogen oxides and sulfur dioxide, the primary causes of acid rain. The CO2 tax would be a powerful incentive for consumers to switch from high-CO2 fuels, such as coal and oil, to power sources that produce less CO2, notably natural gas. When burned, methane generates only half as much CO2 as coal, for example, in producing the same amount of energy.

Ultimately, though, the world must move away from fossil fuels for most of its energy needs. Said Berrien Moore, director of the Institute for the Study of the Earth, Oceans and Space at the University of New Hampshire: "Even if you cut emissions of CO2 in half, the atmospheric concentration will keep going up. You're still adding CO2 faster than you're withdrawing it, so the balance keeps rising."

Of all the known nonfossil energy sources, only two are far enough along in their development to be counted on: solar and nuclear, neither of which generates any greenhouse gases at all. Solar power is especially attractive. It produces no waste, and it is inexhaustible. Not all solar power comes directly from the sun: both wind and hydroelectric power are solar, since wind is created by the sun's uneven warming of the atmosphere and since the water / that collects behind dams was originally rain, which in turn was water vapor evaporated by solar heating.

But wind and hydroelectric power can be generated at only a relatively few sites, and so governments should redouble financing for research to develop efficient, low-cost photovoltaic power. Photovoltaic cells, which produce electric current when bathed in sunlight, were briefly in vogue during the energy crises of the 1970s, and while public attention and Government funding have waned, research into the technology has continued. "The capital costs have come down from about $50 a peak watt to $5," said Speth. If they drop to $1, solar power will become competitive. That could happen without significant Government research support -- but it will happen sooner with it.

Sometime early in the next century, solar enthusiasts hope to see vast tracts of photovoltaic collectors providing cheap electricity that can be transmitted over long distances. Alternatively, the electricity could be used to produce hydrogen from water. That could open up all sorts of possibilities. Cars, for example, could be redesigned to run on hydrogen, and that would produce a dramatic reduction in CO2 emissions.

Nuclear power is more controversial; until recently the mere mention of it made environmentalists blanch. They had good reason, considering the accidents at Three Mile Island and Chernobyl, the problem of radioactive waste and the horror stories about U.S. weapons plants. But the greenhouse effect is forcing some antinuclear activists to rethink their position. "I was a strong opponent of the nuclear program in France," said Brice Lalonde, France's Environment Under Secretary and a former presidential candidate on the Ecologist Party ticket. "Now I am reassessing the whole thing." France gets more than 70% of its electricity from nuclear plants and has an impressive safety record.

Reactors in France, like all conventional reactors, depend for their safety in part on the skill and alertness of their operators. To minimize the risk of human error, engineers have developed designs for much safer types of nuclear reactors. But while these reactors, like experimental solar cells, show great promise, they are not yet economical enough to go on-line in significant numbers. It should therefore be a priority of governments to spend more money on research aimed at lowering the cost of safe nuclear and solar power and making them primary energy sources. Otherwise the global warming that results from overreliance on fossil fuels could produce an increasingly uncertain and potentially bleak future.