In the end, climate change is a math problem.

[Political actions] has to happen on the local and state level; we have to convince our cities to join the growing number of more than 200 American cities who have signed on to the mayor's climate campaign.

I don't think the fossil fuel industry will listen, not until we build up a lot of pressure. I do think we can persuade some shareholders that they don't want to be involved in this enterprise.

No one is strong enough  -  given the magnitude of the task, everyone has to step up their game.

We have to transition to new technologies, making it more expensive to continue with the old and polluting technologies and cheaper to go to the clean ones.

Alone among businesses, the fossil-fuel industry is allowed to dump its main waste, carbon dioxide, for free.

Probably nothing that we have ever managed to do quite equals the basic undermining of the physical stability of the planet on which most of the world's poor people depend.