“You just don't, in the 21st century, behave in 19th-century fashion by invading …” — John F. Kerry

President Obama and I both believe we don't have time for a meeting anywhere of the Flat Earth Society.

It's not enough for one country or even a few countries to reduce emissions when other countries continue to fill the atmosphere with carbon pollution as they see fit.

The solution to climate change is staring us in the face. It's energy policy. If we pursue a global clean-energy economy, we can cut dramatically the amount of carbon pollution we emit into the atmosphere and prevent the worst impacts of climate change.

It's not normal that, when you close your eyes and listen to the news, too often the political back-and-forth in America sounds too much like it does in the kinds of countries that the State Department warns Americans not to travel to.