They began by promoting each other's books. Gingrich said Kerry's new book, "This Moment on Earth: Today's New Environmentalists and Their Vision for the Future," is "a very interesting read" and said he agrees with 60 percent of it. Kerry hasn't read Gingrich's new book on the environment, due out later this year, but said he has always enjoyed their exchanges.
Then the two argued for nearly two hours about whether the government should cap emissions of greenhouse gases or whether tax breaks will encourage businesses to do so.
Kerry said no environmental crisis has ever been solved voluntarily, without government intervention. "That's like saying, 'Barry Bonds, go investigate steroids,' or letting Enron take control of pensions," said the Massachusetts senator and 2004 Democratic presidential nominee.
Libby Quaid reports for AP News, "The arguments were typical for their political parties, although Gingrich is farther to the left of some Republicans who dispute the science behind climate change."
Kerry asked what Gingrich would say to Sen. Jim Inhofe, R-Okla., who calls global warming a hoax.
"My message, I think, is that the evidence is sufficient that we should move toward the most effective possible steps to reduce carbon loading in the atmosphere," Gingrich replied.
He explained that conservatives often worry that the prescription for environmental problems will be bigger government and higher taxes.
Continue reading about the debate here.