TWO things are visible above all at the conference on global warming as nearly 160 nations try to strike a deal by tomorrow:
* The bitter division between rich and poor nations over what is a fair way to cut emissions of "greenhouse" gases.
* The aspirations of the US Senate - with half-a-dozen members taking the trouble to come to Kyoto, Japan - in defining global policy on the environment.
It's too soon to tell whether a substantive agreement will emerge from these meetings. But for the moment, the complexities and frustrations of global problem-solving are on display. "This conference has been highly political," says Peter DeBrine, a climate specialist at the World Wildlife Fund, a leading environmental group. "Politics has prevailed over science and economics."
This conference is the culmination of a five-year-old effort backed by the United Nations that is itself a response to decades of research into human impact on the climate.
But the community of nations is a feisty crowd. There is nothing straightforward about reducing "greenhouse" gases, mainly because to do so would affect national economies, gasoline prices, and almost everything in between.
All but a few nations have ratified the United Nations Framework Convention on Climate Change, a centerpiece of the "Earth Summit" held in Rio de Janeiro in 1992. But their actual efforts to improve the atmosphere have been meager.
As a result, the countries that are party to this treaty decided in 1995 that more rigorous measures were necessary - and it is these new rules that nations are trying to agree upon here in Kyoto.
Without its heat-trapping "greenhouse" of gases and water vapor, the Earth would be an inhospitable 0 degrees F. But for just over a century scientists have worried that human activity - such as the burning of fossil fuels - generates greenhouse gases in quantities that may be sufficient to raise the planet's temperature.
An even slightly hotter Earth would mean, in an extreme scenario, melting ice caps, rising oceans, and the inundation of islands and coastal areas. Some of the more passionate speeches in Kyoto have come from the representatives of South Pacific states.
Negotiators here are trying to come up with a legally binding program under which nations would agree to reduce their emissions of greenhouse gases, mainly carbon dioxide, to 1990 levels or below. But they are stumbling on the issue of fairness.
The Rio convention envisioned that the world's 24 leading industrialized economies, along with Russia and some countries in Eastern Europe, would lead the way in emission reductions. The theory was that these countries had historically generated vast amounts of greenhouse gases and could best afford the measures that could limit future emissions.
Curtailing emissions is a thankless task that can result in lost jobs, higher taxes, and increased energy costs for consumers. Partisans debate just how unpleasant the process would be, but the reluctance of governments to adopt reduction programs demonstrates it is something they would much rather avoid.
In the years since Rio, the developed countries have begun to argue that the world's poorer countries must also engage in this process if there is any hope of achieving significant emission reductions. Countries such as China and India have burgeoning economies that, as they grow, will generate increasingly vast amounts of greenhouse gases.
Besides being fair, the rich countries argue, it is more cost-efficient to implement cleaner practices in developing countries. Not so fast, say officials in developing countries.
"India's per-capita emissions are a very small fraction of many of the world's developed countries," India's environment minister, Saifuddin Soz, told the conference yesterday. "Any idea which seeks further to deprive us of our equitable entitlement to grow" - by imposing environmental restrictions - "can never be allowed to take root."
"The differences between rich and poor countries are still too big," says Ad Lansink, a Dutch official. "They can't sit at the same table and discuss them."
Into this difficulty comes Congress. The Senate this summer passed a resolution - 95 to 0 - warning that it would not ratify any agreement that failed to include the developing countries. Several senators have come to Japan to press their point that the process of emission reduction must be universal.
Sen. Chuck Hagel (R) of Nebraska says he believes that market forces are adequate to pressure countries to reduce their emissions. Any attempt "to artificially set the standard by UN mandate will have disastrous consequences," he argues.
The way through this impasse may be money. Delegates said discussions were under way on a package of financial benefits that would be provided to developing economies in exchange for their agreement in principle to begin reduction measures.
And Sen. John Kerry (D) of Massachusetts says that such an agreement or "acknowledgment" by key developing countries might allow ratification by the Senate.