The Copenhagen conference won't solve the problem of climate change once and for all. Rather than aiming for a broad international treaty, negotiators should strengthen existing national policies and seek targeted emissions cuts in both rich nations and the developing world

The free market has eliminated environmental hazards in the past, from leaded gas to acid rain, and it can solve the problem of climate change today. A cap-and-trade system offers the best hope for reducing pollution and encouraging green growth.

Most initiatives to slow global warming involve reducing carbon dioxide emissions. Little attention has been given to reducing emissions of the light-absorbing particles known as "black carbon" or the gases that form ozone--even though doing so would be easier and cheaper and have a more immediate effect