We have to abandon the conceit that isolated personal actions are going to solve this crisis. Our policies have to shift.

As human beings, we are vulnerable to confusing the unprecedented with the improbable. In our everyday experience, if something has never happened before, we are generally safe in assuming it is not going to happen in the future, but the exceptions can kill you and climate change is one of those exceptions.

We face the gravest threat that civilization has ever confronted. It's global in nature and requires a global solution. Increased CO2 emissions anywhere, whether from China or the United States or from one of the countries that is burning its forests like Brazil or Indonesia.

Tobacco addiction sinks its claws in deeply, it's just as powerful of [sic] an addiction as heroin or crack cocaine.

...the debate among the scientists if over. There is no more debate. We face a planetary emergency. There is no more scientific debate among serious people who've looked at the science...Well, I guess in some quarters, there's still a debate over whether the moon landing was staged in a movie lot in Arizona, or whether the Earth is flat instead of round.

The presidency is more than a popularity contest.

In order to solve the climate crisis, we need to solve the democracy crisis.