The Internet empowers individuals to play a more active role in the political process, as Obama's campaign has manifested.

The mountain glaciers in every region of the world are melting, many of them at an accelerated rate, threatening drinking supplies - drinking water supplies and agricultural water supplies. We have these record storms, drought, floods, fires, three deaths (ph) in the American West, climate refugees beginning now, expected to rise to the hundreds of millions unless we take action.

In an economic recession, naturally, when you ask people to list their priorities, they're going to place a higher priority on the immediate economic situation.

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.

The interior of the earth is extremely hot – several million degrees.

The rule of reason is the true sovereign in the American system.

When our founders created America, it was in the age of the printing press, when individuals could freely join the conversation. And that robust, democratic dialogue more often than not lifted up the best available evidence and asserted what was more likely to be true than not.