In 1992, the EDF worked with Bush Sr. to craft a market system to reduce acid rain. It spurred a revolution in sulfur dioxide scrubbing technologies. The costs were projected at up to $2,000 a ton, but after 10 years they were down to about $100 a ton and emissions were slashed by 50 percent. In 2005, George W. Bush signed off on an additional 70 percent cut. Why? The costs proved so low, the political controversy had disappeared. I suspect the same thing can happen with a cap on global warming emissions once the incentives are right.

The Environmental Defense Fund’s Fred Krupp on the Best Capitalist Climate Solutions