I argue that I don't think it's a moral position to say that civilization is going to collapse, and that's okay. Because that would cause the deaths of billions of people. It's certainly not something I'm willing to accept.

By looking the other way on climate change we facilitate a collective denial, and we do it for each other.

Taking fear seriously is not easy. A lot of people's response to fear is "Don't worry so much, it's crazy." But some things absolutely deserve our fear, and climate change is first among them.

I used to be a lot more afraid of climate change. Now I spend my time working, planning, trying to move forward.

With climate change, of course there are things to grieve. I certainly grieved that the vision that I had for my life, that I would be a clinical psychologist and write books and have a family, that that was not going to happen, because if the world is collapsing around you, it just doesn't seem that appealing anymore.

Psychologically speaking, the rational, healthy response to climate change is to say to oneself, "What can I do about this?" But that question is often answered through individual action.

Social movements throughout history take place in people's minds. If we got 5,000 Americans who were talking about climate change to their neighbors and to their coworkers, and talking about this pledge, that would change the political and social landscape so much more than if 5,000 people got arrested for protesting a pipeline.