I believe [the Department of Energy] should be judged not by the money we direct to a particular State or district, company, university or national lab, but by the character of our decisions. The Department of Energy serves the country as a Department of Science, a Department of Innovation, and a Department of Nuclear Security.

Let me state what the official IPCC prediction is: Sea levels could go up as much as three-quarters of a meter in this century, but there is a reasonable probability it could be much higher than that.

As the saying goes, the Stone Age did not end because we ran out of stones; we transitioned to better solutions. The same opportunity lies before us with energy efficiency and clean energy.

Somehow we have to figure out how to boost the price of gasoline to the levels in Europe.

So imagine a world 6 degrees warmer. It's not going to recognize geographical boundaries. It's not going to recognize anything. So agriculture regions today will be wiped out.

However, when my parents married in 1945, China was in turmoil and the possibility of returning grew increasingly remote, and they decided to begin their family in the United States.

Sustainable energy is the equivalent of the U.S. moon shot.