The economics of climate change is driving what kind of pact nations may be willing to make.
World leaders are becoming fixated on climate change. That's good news. But agreeing with one another about who will do what to slow the warming of the planet won't be easy. The answer is difficult but simple – sit down and get started.
In the coming months, there will be plenty of opportunity. Next weekend President Bush heads to Sydney, Australia, for an economic summit of Pacific Rim leaders. Australian Prime Minister John Howard, who chairs that meeting, has put climate change atop the agenda. In late September the United Nations will hold a climate-change conference, followed closely by a US-sponsored meeting in Washington of the 15 biggest greenhouse-gas emitting countries.
All these lead up to a big climate summit to be convened in Bali, Indonesia, in December. That's expected to produce an international agreement to replace the 1997 Kyoto Protocol, never signed by the US, which expires in 2012.
Maybe scientists can afford to debate the pace and extent of climate change, but the evidence of potential harm is clear enough that economic decisions must be made soon. Those economic choices mean weighing several questions:
Should countries emphasize cutting their greenhouse-gas emissions or adapting to a warmer world? Should they spend on developing new technologies or capping emissions? What's the trade-off between the economic costs and benefits of aggressive action?
Yet another important consideration: How to accommodate the needs of developing countries, many of which may face the worst effects of warming but have the fewest resources to battle it.