Junkies find veins in their toes when the veins in their arms collapse. Developing tars sands is the equivalent.

We now face the prospect of a kind of global civil war between those who refuse to consider the consequences of civilization's relentless advance and those who refuse to be silent partners in the destruction. More and more people of conscience are joining the effort to resist, but the time has come to make this struggle the central organizing principle of world civilizations.

The sooner we switch away from carbon-based fuel and start relying on renewable energy sources available in the United States, the sooner we will grow our economy by creating the millions of new jobs that will come from retrofitting homes and businesses, building smart grids, renewable energy systems and planting trees and all the rest. We need to create a lot of jobs that can't be outsourced.

I want to extend condolences to the families of those who died in the service of the United Nations.

We are running out of time, we must have a planetary solution to a planetary crisis.

The oil industry has outpaced the building of a public consensus of the implications of climate science.

The presidency is more than a popularity contest.