Climate change is the greatest threat of our time.

EPA gets to set a standard for new. For the existing, EPA sets guidelines for what we think is appropriate, but then states develop plans that work for them, taking into consideration their specific energy mix.

I don't think any administration, when they come in, thinks that their job is to tell the scientists what the science looks like or to be quiet about the science. Scientists need to remain true and not allow science to be politicized. Scientists are not politicians, and no politician should consider themselves to be a scientist.

I definitely challenge people. But hopefully, I am working harder than anybody else, and so people won't resent the fact that I want them to work hard, as well.

But I will tell you that I didn't go to Washington to sit around and wait for Congressional action. Never done that before, and don't plan to in the future.

I think that one of our most difficult international challenges is clearly climate change and making sure that the Paris agreement goes forward. While I think the international community understands that President Trump is not taking the same position as President Obama.

When consumers do not take full advantage of efficiency gains, it is because they are weighing other factors that influence their decision making. When the federal government arbitrarily places one of those factors over others, it makes consumers worse off.