Tipping points are so dangerous because if you pass them, the climate is out of humanity's control: if an ice sheet disintegrates and starts to slide into the ocean there's nothing we can do about that.

As a government employee, you can't testify against the government.

I was lucky to grow up at a time when it was not difficult for the child of a tenant farmer to make his way to the state university.

Being at NASA and having the access to both computing capability and satellite observation capability is kind of the ideal research situation to try to understand global climate change.

Global warming isn't a prediction. It is happening.