On the June day that a NASA scientist told Congress that the "greenhouse effect" may be linked to the devastating drought and withering heat of 1988, the mercury hit 98 degrees in the nation's capital, crept up to 90 degrees in Cincinnati, soared to 97 in Dallas and topped 100 in Nashville.
Newspapers and television were telling of the drought's ravages: Crops were beginning to fail and farmers were desperate. A seemingly unrelated global environmental issue - the alarmingly rapid depletion of the world's ozone layer - was in the news, too. After years of doubts and skepticism, the world's political leaders and industries had accepted that a man-made chemical was destroying the stratospheric layer that shields the planet from harmful ultraviolet rays and protects against such ills as skin cancer.The combination of these circumstances gave the NASA scientist's pronouncement a telling edge: Whether people accepted his opinion that the current drought and heat could be greenhouse phenomena, they now had a framework for understanding the kind of misery that such a global warming could bring. Moreover, the depletion of the ozone proved the planet's vulnerability to man.
"First of all, the hole in the ozone woke everybody up to the fact that humans can in fact destroy the life-support systems that nature provides us," said Michael Oppenheimer, an atmospheric physicist and senior scientist with the Environmental Defense Fund in New York. "And second, the hot summer across most of the country has given people a visible example of how miserable life can get with even a modest warming."
So, nearly 100 years after the first scientific paper on the greenhouse effect was published, the world is taking notice. Interest in global warming has exploded in Congress and among world organizations, rapidly taking the topic from the laboratory to the living room.
"If you go by the average taxicab driver, a lot of people have become aware of this issue and sensitized to it," said Dennis Tirpak, director of strategic studies for the U.S. Environmental Protection Agency.
But will the public interest fade when the temperatures drop and the rains begin? Is the debate little more than an overnight sensation, sparked by an unnerving set of circumstances and a dearth of summertime news? Is change in policy and regulation imminent?
Global warming is not the only environmental issue that has moved closer to the top of the public agenda in recent months. Other global problems, including ozone depletion and deforestation, also are increasingly capturing public attention. In many ways, they are linked. Chlorofluorocarbons, or CFCs, the man-made chemicals that destroy the stratospheric ozone shield, also act as a greenhouse gas in the troposphere. The loss of tropical forests around the world is believed to contribute to global warming because the forests emit carbon dioxide, another greenhouse gas, when they die and absorb it when they grow.
The greenhouse effect is caused by the buildup of carbon dioxide, emitted by the combustion of fossil fuels by cars and factories, and other gases that accumulate in the atmosphere. These gases trap the Earth's heat, acting much like a greenhouse.
Atmospheric scientists suggest that the temperature rise may eventually melt glaciers, raise sea levels, transform verdant farmland into des-ert and usher in an increasing number of days of sweltering heat.
Scientific projections vaguely suggest that the climatic disruptions will occur gradually in the 1990s and increase in severity into the next century. But James E. Hansen, the National Aeronautics and Space Administration scientist who testified before Congress, proclaimed that the greenhouse effect has arrived and cited as evidence the fact that the first five months in 1988 were the hottest on record. In the current Journal of Geophysical Research-Atmospheres, a team lead by Hansen reported that a computer model shows the Midwest Farm Belt and the Southeastern United States may be among the first regions of the planet to experience the warning.
While not all scientists agree that this year's higher temperatures can be attributed to the greenhouse effect, most argue that a significant global warming is inevitable, even if massive measures are immediately taken to halt air pollution.
Reams of legislation are now being introduced in Congress to reduce emission of greenhouse gases. Unlike past greenhouse legislation, which generally called for more study of the problem, two new bills introduced this summer would force drastic changes, possibly even upheaval, in industry and lifestyle. Both measures have attracted surprisingly broad congressional support, considering their sweeping scope, and lawmakers predict parts of them will be enacted this year or next.
"It (the greenhouse effect) is so much more comprehensive, so much more dangerous, so much more revolutionary, so much more life-changing than anything else we have done that it literally means everything as far as this Congress is concerned and as far as our life styles and our very economy is concerned," said Sen. J. Bennett Johnston, D-La., an ally of the oil industry who shocked many by speaking out in favor of one of the bills.
Balking only at endorsing a provision that would require cars to average 55 miles a gallon by 2010 - twice the 1985 efficiency standard - Johnston announced: "We'll have to begin the serious process of legislating (in 1989). We'll act as fast as the public's willing to support us."
Industry is also slowly, and in some cases grudgingly, beginning to devote more money and staff to research the ramifications of the warming and prepare for regulations that could require major product redesigns.
General Motors, for instance, is investigating the use of new fuels that would not emit carbon dioxide. The Electric Power Research Institute in Palo Alto, Calif., a private research funding organization financed largely by the utility industry, spent about $2 million on greenhouse research during the past eight to 10 years and now is spending at a rate of $2.5 million every two years. "And I'm sure it's going to rise in the near future," said Ralph Perhac, director of the institute's environmental science department.
Trade associations are increasingly asking greenhouse experts to hold workshops and seminars for their members. "We're starting to pay a good deal of attention to it," said Arthur Wiese, a spokesman for the American Petroleum Institute.
But Wiese, like other representatives of industry groups, insisted that legislation calling for dramatic changes in energy and environmental policy is premature until further research proves that the warming trend is accelerating.
On the international level, discussion of the greenhouse effect is no longer limited to scientific meetings. A recent world conference in Toronto on the changing atmosphere marked a turning point in the kind of international attention the problem is receiving, the EPA's Tirpak said. Previous international conferences on the subject had been more science-oriented, dominated by the "in-group" of international climate scientists, he said.
"For the first time, you had the prime ministers of Canada and Sweden and a number of ministers from developing countries all attending a meeting and making proposals to deal with this issue," he said. "When you begin to have people at that level become interested, I guess you can say it has moved from strictly a science issue to a political issue."
Upcoming studies and conferences on the greenhouse effect suggest that the issue will not disappear from the public consciousness. The clamor may soften when the climate cools, but the scientific and public policy debates that helped put the greenhouse effect in the headlines will continue.
Two major studies by the Environmental Protection Agency will keep the issue before the public until at least the end of the year: One will examine how the climatic trend will affect agriculture, health, energy, air pollution and forestry; the other will set down policy options that would help stabilize the atmosphere.
Over the coming year, the Germans, Italians, Dutch and possibly the Canadians will each hold an international conference on global atmospheric issues. In addition, the second World Climate Congress, sponsored by the World Meteorological Organization, will be held in 1990, with the greenhouse effect a major part of its agenda.
How rapidly such attention will lead to policy change or regulation is unclear. The EPA policy report, for example, will not contain an analysis of costs or the feasibility of various proposed technologies. "I think there will be a great deal more work needed," Tirpak said.
The report is expected to encourage use of alternative energy sources, improved energy efficiency in the residential, commercial and transportation sectors, more reliance on natural gas as an interim transition fuel and the use of more efficient coal technologies.
Although parts of the recently introduced greenhouse legislation may be passed by Congress within the next year, both bills are expected to encounter stiff opposition from various industries, including coal production and automobile manufacturing. U.S. industry in general strongly opposes any unilateral action by the United States, arguing that only a global solution can work.
Sen. Timothy E. Wirth, D-Colo., who recently introduced one of two bills, said he was surprised when it quickly captured 20 co-sponsors. His $4.2 billion proposal would profoundly change the direction of U.S. energy policy toward use of energy-efficient appliances and cars and non-polluting energy sources.
"It is very hard to pass a bill this broad and comprehensive," he said, adding that his purpose is to "frame the issue" in hearings this year before any legislative action is taken.
The other main greenhouse bill, sponsored by Sen. Robert T. Stafford, R-Vt., seeks a 50 percent cut in carbon dioxide emissions by the year 2000 and a 75 percent cut by 2010.
A new administration in the White House is also expected to ease the path for new policy. Massachusetts Gov. Michael S. Dukakis, the Democratic presidential nominee, favors holding an international summit on the environment with other heads of state during his first six months in office. The greenhouse effect would be at the top of the summit agenda, said Thomas D. Herman, Dukakis' deputy national issues director.
Vice President George Bush, the Republican candidate, on Wednesday proposed a similar global meeting on environmental issues, including the greenhouse effect.