With weekend rallies planned nationwide to highlight the problem, Gingrich, a Republican, said the solution must be a partnership between environmental interests and economic interests, with economics playing a key role.

Kerry, however, said it won’t work to just let the market regulate itself. “No single environmental crisis” in the history of the United States has been “resolved voluntarily,” he added, and that’s why government regulation is needed.

Gingrich argued that Kerry’s approach would be unlikely to attract China and India and that “no strategy which does not bring in China and India” will work. He also acknowledged the conflicting interests. “If you ask (countries) to choose between the environment and economic growth, (they) are going to choose economics,” he said.

Despite differences, Kerry and Gingrich predicted a successful end to the climate-change crisis. “It’s very important to recognize the adaptability of humans,” Gingrich said. “I think that we have to have optimism.” Added Kerry, “The American genius will meet this challenge.