Quotes of the Day

In the Indonesian capital of Jakarta, traffic moves as slowly as blood through a corpse. Streams of motorcycles part for SUVs and diesel-spewing buses, and everyone gets nowhere fast. The air is smeared, both from the vehicle exhaust and the frequent forest fires that break out around Indonesia. Once home to some of the most extensive rain forests in the world, Indonesia is now losing trees at a faster rate than any other nation, to flames but also to rampant logging. Since equatorial trees soak up carbon dioxide when they're alive and release the gas when they're cut down or burned, Indonesia's rapid deforestation is the main reason why this country of 245 million is the third biggest carbon emitter in the world after the U.S. and China. But as in other developing countries, the Indonesian government says it needs to focus on economic growth to raise its people out of poverty—and that likely means that trees will be cut, cars will be added and carbon emissions will only go up.

Keep Indonesia in mind as the world digests the third and final chapter of the Intergovernmental Panel on Climate Change's (IPCC) latest assessment on global warming, which was released last week in Bangkok. While the first two sections made for depressing reading—nailing down the scientific basis for global warming and laying out nightmare scenarios of the havoc climate change could wreak—the last chapter is comparatively optimistic. Drawing on the work of thousands of scientists vetted by officials from over 100 countries, the IPCC reported that future carbon emissions could be controlled using current technology like nuclear or renewable energy—and that it could be done without bankrupting the global economy. "Measures to reduce emissions can, in the main, be achieved at starkly low costs, especially when compared with the costs of inaction," said Achim Steiner, executive director of the United Nations Environment Programme (UNEP). European environment commissioner Stavros Dimas drilled home the message: "There is no excuse for waiting."

But while the technological path to climate-change action is clear, the politics are getting more complicated. As economic growth shifts to the developing world—especially Asia—so will future carbon emissions. Whether the world can effectively combat climate change will be determined by countries like Indonesia and India—and particularly China, which could pass the U.S. as the world's top carbon emitter any day. European nations have staked out bold positions on carbon cutting, and momentum is growing in the U.S. for real climate-change legislation. But if developing countries choose to ignore global warming, even the most radical actions out of the developed world could be rendered meaningless.

The worrying news is that over the past several months, China in particular has begun to replace the U.S. as the main obstacle to stronger action. During the IPCC negotiations that took place last week in Bangkok, Chinese delegates—with the support of India and other developing nations—tried to tone down the report, pushing to remove the most ambitious possible targets for future carbon-emission levels. The move failed, but it's unlikely to be the last time China and India drag their feet on climate change. "It's clear that the developed world will not move without something from the developing nations," says Eileen Claussen, president of the Pew Center on Global Climate Change. But at the same time, she adds, "there's no chance of getting China unless the U.S. steps up."

Because developing nations have emphasized that they can't afford to jeopardize the pace of economic growth for the sake of the environment, the only climate-change solutions they're likely to accept will be ones that come cheap. Fortunately the IPCC says that's possible—the new report concludes that the cost of stabilizing global carbon emissions by 2030 could require as little as one-tenth of a percentage point per year of global growth through the end of the century. Those costs will have to be borne by someone, and the developing nations will rightly push for North America and Europe to pick up the check. Expect that argument to be renewed at the next major U.N. climate-change meeting in Bali, Indonesia, at the end of the year.

Developing nations make the point that they're not responsible for the vast majority of carbon dioxide hanging around in the atmosphere—which was put there by Western countries during their own development over the past 150 years. They argue that their own per capita-emissions rates are still far lower than those of the West, and that, therefore, climate change isn't their responsibility. But future global warming will hinge on how we deal with future carbon emissions—most of which will come from developing Asia. The center of gravity of climate-change politics has moved to China, India and Indonesia. Their decisions will shape the world we live in.

• Bryan Walsh