Where solar energy is concerned - and wind energy and battery storage and electric vehicles and efficiency technologies - that is what we are now seeing. So, yes, I'm very optimistic, but anyone who works on the climate crisis has an internal struggle between hope and despair. I won't deny that, but hope has always prevailed in my outlook.

There's no such thing as clean coal. It's non-existent. Theoretically, it might be possible, many years from now, to come up with a way to clean it as it's burnt. But there's not a single demonstration project in the United States. [...] Clean coal doesn't exist.

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

It's an important point, and every little bit helps not least because those who make those kinds of changes are more likely to make their voices heard as citizens. But the ultimate solutions are going to come through policies.

I'm old enough to know that a red carpet's just a rug, and I've been able to enjoy the pageantry without letting it go to my head.

Now we have things that are obviously false, leading us to war, leading us to deny people health care, leading us to ignore the climate crisis. We have to restore the integrity of the democratic conversation.

Iraq does pose a serious threat to the stability of the Persian Gulf and we should organize an international coalition to eliminate his access to weapons of mass destruction. Iraq's search for weapons of mass destruction has proven impossible to completely deter and we should assume that it will continue for as long as Saddam is in power.