Human understanding of climate change is subject to profound uncertainties about causes, effects, and rates of change.
The international community formed a groundbreaking framework for dealing with global warming in the 1992 Climate Change Convention, ratified by 184 countries, and the 1997 Kyoto Protocol, signed by 84 countries.
The Kyoto Protocol requires industrialized countries to cut six greenhouse gases, including carbon dioxide, to roughly 5 percent below 1990 levels.
The signatories have been negotiating for three years on how to implement the protocol, and are ending a two-week session this week in Lyon, France, in the lead-up to a meeting of world leaders in The Hague in November.
At issue is whether or not there should be sanctions against countries that fail to meet their commitments, and what kinds of flexibility there will be for countries who need it.
Curiously, recent statements from two leaders in the effort to combat global warming have confused the discussion and could work against the effort.
Eileen Claussen, head of the Pew Center on Global Climate Change and a former State Department official, has long championed countries adopting protocol measures before the Kyoto agreement enters into force.
In widely publicized comments, most recently in the British journal Nature, Ms. Claussen suggested that an honest and realistic foundation is required for any international protocol. True enough. But she went on to say that lack of progress toward the targets suggests we should relax those targets -instead of stepping up our efforts.
Currently, the UK is the only industrialized country that is likely to meet the Kyoto targets. The US, on the other hand, has increased emissions by about 11 percent from 1990 levels. Most other countries are between these two extremes.
This is not as hopeless as it sounds. If compliance with the protocol required only domestic action, the industrialized countries would never have agreed even to its modest goal. That's where "flexibility mechanisms" come in -means for industrialized nations to obtain "credits" from nations that are well within their targets and from developing countries.
Ignoring the "flexibility" built into the Kyoto agreement and renegotiating the emission-reduction commitments would be twice flawed.
It plays into the hands of entities - such as the Global Climate Coalition (GCC), an umbrella group representing heavy industry - that waged a $30 million campaign to discredit the science behind the Kyoto agreement, and questioned the wisdom of the protocol because of alleged economic losses to the private sector.
The GCC heartily endorsed Claussen's comments, of course. Renegotiating the targets would slow the pace of ratification and implementation. If the protocol never enters into force, there is no way to amend its language.
The suggestion that nations completely ignore the progress made so far, drop any further consideration of the Kyoto Protocol, and form a new agreement from scratch, is not truthful to the science of climate change, to the integrity of past agreements hard won among the nations, nor to the political realities of the world community.
James Hansen, who directs NASA's Goddard Institute for Space Studies in New York, has long been an effective spokesman on global warming. It was Hansen who told a congressional committee in 1988 "it is time to stop waffling ... the greenhouse effect is here."
In a paper published by the National Academy of Sciences in August, Dr. Hansen and colleagues observe that global warming has been driven strongly by gases other than carbon dioxide, such as methane, ozone, and chloroflurocarbons, and has been influenced by aerosol pollution.
Efforts might be better focused, they say, on controlling these gases instead of carbon dioxide, thereby avoiding "economically wrenching actions."
Several studies have been carried out, primarily in the industrialized countries, giving varying estimates on the cost of reducing fossil-fuel use. A selection of these studies was used by GCC to discredit any action.
Recent studies of New England have shown that large financial savings and net gains in employment can be made through conserving energy and shifts to alternative sources. These gains become more attractive daily as the prices of fossil fuels continue to rise.
Further, Hansen and his colleagues are saying nothing new. Carbon dioxide contributes about half of the warming potential, while other heat-trapping gases contribute the remainder.
Aerosols in the atmosphere appear to have masked the effect, delaying the warming. Relying on atmospheric pollution with aerosols to stabilize global climate is little short of foolish.
Stabilizing the atmosphere will require every effort to control all the heat-trapping gases, and there is no margin for further delay.
Even Hansen and colleagues assert in their controversial paper that carbon-dioxide concentrations will have to be controlled in the end.
They are assuming, with no information and no experience, that the ecological effects of the warming so far are minor and acceptable; that further delay in stabilizing the atmospheric burden of heat-trapping gases is not a serious risk; and that action to check carbon-dioxide emissions is expensive and undesirable.
Placing an emphasis on gases other than carbon dioxide will be seen by the developing nations as an attempt to shift the burden onto developing countries, who believe they are seen as major sources of methane through rice culture and cattle.
Hansen's paper further arms groups like GCC to argue that the burden should be shifted to developing countries.
Aspirations under the Kyoto Protocol are modest. The challenge before the world community is by contrast immense - to ensure that the protocol is enacted (which means agreeing on rules governing flexibility mechanisms), while we develop a framework that assures far more rapid reductions in the future.
The need of the hour is incremental progress on this important global issue. It is unfortunate that well-intentioned and highly respected leaders should suddenly open the possibility of further costly political confusion, delay, and the hazards and soaring expenses associated with such delay.
*Kilaparti Ramakrishna is the deputy director of the Woods Hole Research Center in Woods Hole, Mass., and was a special adviser to the UN in drafting the Framework Convention on Climate Change. George M. Woodwell is the center's director.
(c) Copyright 2000. The Christian Science Publishing Society