More to the point, unilateral action will not mitigate climate change. The U.S. is only a small fraction of total emissions. Even if all of the Annex I countries of the Kyoto Protocol agreed to binding constraints, they would account for less than half of the world?s total emissions, and a far smaller fraction of the expected growth in emissions between now and 2100. To act unilaterally, or even in conjunction with the rest of the developed world, would mean paying the full measure of mitigating climate change while receiving only a fraction of its benefit.