Hot Times All Around

　　（1）If good intentions and good ideas were all it took to save the deteriorating atmosphere,the planet's fragile layer of air would be as good as fixed.The two great dangers threatening the blanket of gases that nurtures and protects life on earth—global warming and the thinning ozone layer—have been identified.Better yet,scientists and policymakers have come up with effective though expensive countermeasures.

　　（2）But that doesn't mean these problems are anywhere close to being solved.The stratospheric？ozone layer,for example,is still getting thinner,despite the 1987 international agreement known as the Montreal Protocol？which calls for a phaseout of chlorofluorocarbons （CFCs）？and other ozone-depleting？chemicals by the year 2006.

　　（3）CFCs—first fingered as dangerous in the 1970s by Sherwood Rowland and Mario Molina,two of this year's Nobel-prizewinning chemists—have been widely used for refrigeration and other purposes.If uncon-trolled,the CFC assault on the ozone layer could increase the amount of hazardous solar ultraviolet light that reaches the earth's surface,which would,among other things,damage crops and cause cancer in humans.Thanks to a sense of urgency triggered by the 1985 detection of what has turned out to be an annual holein the especially vulnerable ozone over Antarctica,the Montreal ______ have spurred industry to replace CFCs with safer substances.

　　（4）Yet the CFCs already in the air are still doing their dirty work.The Antarctic ozone hole is more severe this year than ever before,and ozone levels over temperate？regions are dipping as well.If the CFC phaseout proceeds on schedule,the atmosphere should start repairing itself by the year 2000,say scientists.Nonetheless,observes British Antarctic Survey meteorologist Jonathan Shanklin:It will be the middle of the next century before things are back to where they were in the 1970s.Even that timetable could be thrown off by interna-tional smugglers who have been bringing illegal CFCs into industrial countries to use in repairing or recharging old appliances.Last year alone 20000 tons of contraband？CFCs entered the U.S.—mostly from India,where the compounds are less restricted.

　　（5）Developing countries were given more time to comply with the Montreal Protocol and were promised that they would receive $250 million from richer nations to pay for the CFC phaseout.At the moment,though,only 60% of those funds has been forthcoming.Says Nelson Sabogal of the U.N.Environment Program:If devel-oped countries don't come up with the money,the ozone layer will not recover.This is a critical time.

　　（6）It is also a critical time for warding off？potentially catastrophic climate change.Waste gases such as car-bon dioxide,methane？and the same CFCs that wreck the ozone layer all tend to trap sunlight and warm the earth.The predicted results:an eventual melting of polar ice caps,rises in sealevels and shifts in climate pat-terns.

　　（7）Delegates to the 1992 Earth Summit in Rio passed a resolution urging industrial countries to reduce emis-sions of greenhouse gasesto 1990 levels,mostly by increasing energy efficiency,but the agreement was purely voluntary—and exempted developing nations.The industrial countries were also asked to help devel-oping nations switch to less polluting technology in a program known as joint implementation.Unfortunately,that would take money,and industrial nations are not in a spending mood these days.A few pilot projects have gone forward.Three U.S.utilities are building a gas-fired power plant in the Czech Republic to replace a coal-burning plant,and Japan is exploring similar ventures in China.For the most part,though,getting developed countries to sponsor such programs has proved difficult.Inside the industrial world,emission-reduction efforts have been most successful in ecology-minded Germany and Japan.But in the U.S.,the world's biggest green-house polluter,legislators want to cut taxes rather than boost spending.

　　（8）Until recently,slackening governments could point to scientific uncertainty about whether global warming has started,but that excuse is wearing thin.A draft report circulating on the Internet has proclaimed for the first time that warming has indeed begun.Global average temperatures have risen about 1℃ in the past century,and human activity is almost certainly part of the cause.It's as clear a record as we can possibly get of a warming trend,says Tom Wigley,a senior scientist with the U.S.National Center for Atmospheric Research and a con-tributor to the U.N.-sponsored Intergovernmental Panel on Climate Change （IPCC）,which produced the re-port.

　　（9）The draft report says temperatures will probably continue to rise,jumping as much as 5℃ over the next century.That will be the biggest increase since the warming that ended the last Ice Age—but this one will be taking place over decades,not centuries.That means sea levels will rise,flooding coastal areas and river deltas and endangering more than 100 million people.Beyond that,rainfall patterns will undoubtedly change,disrupt-ing agriculture.And weather extremes of all kinds will get more extreme.Hurricanes and typhoons are pre-dicted to become more powerful and destructive;wet areas are likely to get wetter,triggering floods,while hot,dry parts of the world could get even more arid.

　　（10）Because the changes will be rapid,natural ecosystems—wet lands,rain forests,savannas—may be unable to adapt.Animals and plants that have evolved to live under a certain set of climate conditions will sud-denly face different circumstances.Many will go extinct.And the potential for deadly disease outbreaks will rise:warming waters will be more hospitable to germs like those that cause cholera？disease carriers such as the Aedes aegypti mosquito may find they can survive nicely in places like northern Europe and the U.S.,mak-ing illnesses such as malaria？more widespread.

　　（11）The good news is that this gloomy scenario？may galvanize？the world's governments into taking serious action.The first line of attack,says Florentin Krause,an IPCC contributor and director of the California-based International Project for Sustainable Energy Paths,should be no regretsactions—changes that will be beneficial no mater how much of a threat global warming turns out to be.Among them:promoting the use of energy efficient appliances and cars.But the IPCC report,says Krause,makes it clear that nations must do more.For example,though it's now more costly to generate electricity from solar cells than from gas or coal,using the sun's clean energy could save money that would otherwise have to be spent in the future combatting the effects of global warming.

　　（12）The encouraging precedent is the Montreal Protocol for ozone protection,which showed how quickly na-tions can act when they finally recognize a disaster.A related lesson is that if CFCs do disappear,it will be partly because chemical manufacturens discover they can make a profit by selling safer replacements.The same process may ultimately be what relieves global warming.After long years of effort,manufacturers of solar-power cells are at last close to matching the low costs of more conventional power technologies.And a few big orders from utilities could drive the price down to competitive levels.If that happens,then all nations,from the rich to the poor,may end up working to save the atmosphere for the same reason they've polluted it:pure eco-nomic self-interest.