BERLIN — A DAREDEVIL activist here did his part to draw attention to the environment by trying to walk nearly 2,000 feet on a tightrope without a safety net on March 26. Buffeted by wind and rain, however, he soon abandoned the journey.
Delegates to the Berlin climate conference that opened March 28 will have to tread just as gingerly toward their goals.
The main topic at Berlin is global warming. Beyond a consensus that Earth's temperatures are rising, all other issues are on the table in a debate that addresses everything from whether melting polar ice caps could sink Amsterdam to whether pollution controls will cost countless jobs in the United States.
The follow-up to the 1992 Earth Summit held in Rio de Janeiro, held under the auspices of the United Nations, runs through April 7. Representatives here at the First Conference of the Parties to the UN Convention on Climate Change -- who come from 150 nations -- will be hard pressed just to define the questions they want to address, let alone find the answers.
''There is a minefield of conflicting issues. This conference will have to steer itself through this minefield,'' said Timothy Wirth, US undersecretary of state for global affairs. 'To have a balanced [environmental] program with sustainable development means a balance between the environment, the economy, and the institutions necessary for human beings.''
Swimming through Bangladesh?
Many people see the threats of global warming -- such as the melting of polar ice caps -- as remote. But the resulting rise in ocean levels could submerge low-lying coastal areas, especially in island nations and countries like the Netherlands and Bangladesh, which annually experiences floods.
On the other end of the scale, weather patterns that shift with warming could widen deserts and worsen droughts, leading to famine and mass migration. Some environmental groups, including Greenpeace, describe the situation as ''the climate time bomb.''
But acting to reduce global warming is sure to stir tension between the rich and poor nations, as well as threaten economic growth worldwide by curbing industry, and few predict the Berlin meeting will achieve any breakthroughs. A preparatory meeting in New York in February failed even to set an agenda for Berlin. Most world leaders aren't planning to attend this summit, which comes less than a month after the UN-sponsored social summit in Copenhagen.
''The problem is that every decision must be made by consensus,'' Angela Merkel, the German environment minister and nominal summit host, said at a recent news conference. ''This is why we can't expect a protocol to come out of Berlin, only a mandate to negotiate a protocol.''
An agreement to discuss later
Mr. Wirth, the US environmental trouble-shooter, says that if the Berlin summit is to be a success, delegates must pledge to discuss reducing CO2 levels by 1997. That protocol, in turn, must set long-term aims for combating global warming, establish feasible measures, and define what actions are to be taken by each nation.
The main stumbling block in the debate is linked to the role of carbon dioxide (CO2) in warming. Many scientists say CO2 and other gases are causing the ''greenhouse effect,'' basically creating a layer of pollution that traps radiation in the atmosphere, allowing the earth to heat up.
Curbing emissions of so-called greenhouse gases would restrain the global-warming trend, scientists add. Some of the largest sources of CO2 are emissions from fossil fuels used in the operation of power plants, industry, and autos.
At the Rio climate summit almost three years ago, industrialized countries pledged to reduce CO2 emissions to 1990 levels by the year 2000. Poorer nations -- including China, the world's third-biggest producer of greenhouse gases -- were not held to the commitment.
Most industrialized countries are having trouble cutting back on CO2. Wirth, for example, insisted the US government is committed to meeting the Rio target, but could not guarantee success. At the same time, he said long-term measures to curb auto emissions would reduce CO2 significantly starting in 2010.
Germany pledged the most of all industrialized nations in Rio: To cut emissions between 25 to 30 percent by 2005, compared with 1987 levels. Ms. Merkel says Germany has already achieved a significant reduction, thanks largely to the ''Wall-fall profit.''
German reunification in 1990 forced the least-efficient and most polluting factories in the former East Germany to close. Yet the German government balks at introducing speed limits on highways, a move that could sharply reduce auto emissions.
Many environmentalists say the Rio pledge, even if met by industrialized nations, is insufficient to defuse the global-warming time bomb. The growth of CO2 emissions in poorer countries, if it continues at its current pace, will by 2010 reach levels that are as high as the entire world's output was in 1970, according to EarthAction, an umbrella organization of more than 1,000 environmental groups worldwide.
Some Berlin conference participants want to reduce CO2 emissions, based on 1990 levels, by 20 percent by 2005. But the proposal appears to stand little chance of gaining the necessary unanimous acceptance, though some countries are pushing to have decisions made by majority vote instead.
Opposition is coming from a coalition of the business lobby in some industrialized states, along with oil-producing and various poorer nations.
The Global Climate Coalition, a Washington-based lobby group comprising US trade associations and private companies, is one of the organizations that says more research is needed before steps to curb CO2 emissions can be adopted.
''Our primary goal is to make sure policy doesn't get way out ahead of science,'' said coalition spokesman Don Rheem.
The GCC disputes the theory that CO2 is the leading cause of global warming, saying scientific models are still too imprecise to pinpoint the causes, rates, and effects of warming. Hasty action could produce economic upheaval and social tension in the industrialized world, without having any effect on warming.
Scientists largely agree that average temperatures have risen about 1 degree F. since the mid-19th century. But they have not proved conclusively that global warming is a man-induced phenomenon, not a naturally occurring event.
The GCC also resists CO2 reduction measures -- even though the US produces the most CO2 in the world -- arguing that the United States would suffer disproportionally if it tries to cut back. Citing a Department of Commerce study, the group says US living standards would plummet and unemployment would rise significantly if the US tried to cut CO2 emissions by just 10 percent, based on 1988 levels, by 2010.
Meanwhile, oil-producing nations, including Kuwait and Saudi Arabia, have indicated they will block anything that threatens to reduce the demand of their primary means of national livelihood.
Poorer nations, China in particular, may prove the toughest to win over to the CO2 emissions-reduction cause. Many see calls to cut back as a new way to keep them dependent on wealthier countries.
In the so-called North-South debate, industrialized nations, lying mostly in the Northern Hemisphere, say the developing countries are the future source of the majority of CO2 emissions, and therefore must take action.
Officials and environmentalists in poorer countries, located largely in the Southern Hemisphere, counter that most emissions to date have been generated by industrialized nations, which should bear more responsibility.
The North is trying to ''pass the carbon-dioxide buck,'' says Atiq Rahman of the Bangladesh Center for Advanced Studies in Dhaka. ''If everyone in the South stopped breathing, the planet would still not be sustainable if the North keeps polluting.''
Learning to share fair
Particularly contentious is the concept of ''joint-implementation,'' under which industrialized nations would share environmentally clean technology with poor nations. Gains in cutting emissions would be credited to both the donor and the user nation. Working out details has proved difficult, however, as potential participants haggle over percentages.
Poorer countries want to take part in developing and producing clean-air technology, not just receive it, Mr. Rahman and others say. Joint implementation as it is now conceived would mean ''the continuation of economic distortion. It wouldn't just prolong, but enhance worldwide inequality,'' Rahman added.
Regardless of whether greenhouse gases are the principal culprit in warming the planet, the threat remains if temperatures rise at their projected pace. According to a UN brochure prepared for the Berlin conference, ''scientific consensus'' predicts that temperatures will rise 2 to 8 degrees F. over the next century, which could shift weather patterns -- bringing on melting ice caps and widening deserts.
''We're talking about the lives of millions of people,'' Rahman says.