Climate change is the greatest threat of our time.

I cannot shy away from controversy. I don't know if it's my Irish blood, but I love it.

There is no threshold level of fine particle pollution below which health risk reductions are not achieved by reduced exposure.

The climate change is real today, but also the solutions that we have available to us that are cost-effective and beneficial to everyone are at our disposal now.

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.

But just [proposing the standard] puts companies on notice that if you're looking to construct a new natural-gas or coal facility, you really need to pay attention to these. This is what they should be designing new facilities toward as soon as this proposal hits the streets.

States with tremendous oil and natural gas reserves have the most to gain economically from proper regulation.