The world beyond 450 ppm atmospheric concentrations of carbon dioxide, the world that crosses carbon cycle tipping points that quickly take us to 1000 ppm, is a world not merely of endless regional resource wars around the globe. It is a world with dozens of Darfurs. It is a world of a hundred Katrinas, of countless environmental refugees

The last time Earth was 1°C warmer than today, sea levels were 20 feet higher.

Ideology trumps rationality. Most conservatives cannot abide the solution to global warming - strong government regulations and a government-led effort to accelerate clean-energy technologies in the market.

If Americans in 2100 came to see 12 meters sea-level rise as inevitable by 2200, who can even begin to fathom how the nation would respond?

I've always believed that you should stick as closely to the science as possible. And my biggest advice to reporters has been, if you're doing a climate story, talk to climate scientists. The best climate stories are done by the people who talk to climate scientists.

The best thing about improvements in health care is that all the climate-change deniers are now going to live long enough to see how wrong they were.

On our current path, all our great Gulf and Atlantic coast cities are at risk of meeting the same fate as New Orleans.