As I have said for many years throughout this land, we're borrowing money from China to buy oil from the Persian Gulf to burn it in ways that destroy the future of human civilization. Every bit of that has to change.

In the age of the internet, with all of its problems, over time, the very fact that individuals can join the conversation creates the opportunity for the emergence of - for the re-emergence of a genuine conversation of democracy.

Political will is a renewable resource, and everyone can have it in abundance if they so choose.

Population growth is straining the Earth's resources to the breaking point, and educating girls is the single most important factor in stabilizing that. That, plus helping women gain political and economic power and safeguarding their reproductive rights.

I understand that being optimistic in this age is challenging, but I am optimistic nonetheless.

There's no such thing as clean coal. It's non-existent. Theoretically, it might be possible, many years from now, to come up with a way to clean it as it's burnt. But there's not a single demonstration project in the United States. [...] Clean coal doesn't exist.

A zebra can not change it's spots.