Eventually we'll use a CO2 tax offset by a reduction in taxes elsewhere alongside a cap-and-trade plan, but the degree of difficulty associated with a CO2 tax far exceeds that with a cap-and-trade plan. We're seeing it's hard to get a cap-and-trade plan and it's much easier to use as a basis for a global agreement than a CO2 tax.

I take no pleasure in the fact that the scientific predictions I’ve relayed to popular audiences turn out to be true.

There's a law of physics: For every action there's an equal and opposite reaction. And sometimes that shows up in politics and society. And I think that the reaction to President Trump's decision on the Paris Agreement has been much stronger than I had even hoped for. And the determination being expressed by so many people in state governments, city governments, in the business community, the investor community, is really heartening to me.

I'm sorry I ever invented the Electoral College.

If there is no cost to be paid for the indiscriminate dumping of pollution into the earth's atmosphere, then it should be a surprise to no one that today we will dump another 70 million tons of global warming pollution into the thin shell of atmosphere surrounding our planet. ... We have to [act] this year, not next year. Mother Nature does not do bailouts.

If you want your energy bills to go up, you should support an ever greater dependence on foreign oil, because the rate of new discoveries is declining as demand in China and India is growing, and the price of oil and thus the price of coal will go sky high.

The truth is that climate change is presenting the greatest challenge humanity has ever faced.