The first few feet of sea-level rise alone will displace more than 100 million people worldwide and turn all our major Gulf and Atlantic coast cities into pre- Katrina New Orleans - below sea level and facing super-hurricanes.

On moral grounds, I think that if you believe a certain outcome is a very possible outcome, you have an obligation to tell people that. With global warming, the probability of a bad outcome if we stay on our current emission trends is incredibly high. If you know a bad outcome is likely to happen, what right do you have not to communicate that? You go into a doctor's office, what are they going to do - not tell you the diagnosis?

The United States could dramatically reduce its carbon emissions per kilowatt-hour without raising its overall energy bill.

When people ask me what they should do, I reply, "Get informed, get outraged, and then get political."

We created a way of raising standards of living that we can't possibly pass on to our children.

The best thing about improvements in health care is that all the climate-change deniers are now going to live long enough to see how wrong they were.

Time is short. We have at most a decade to sharply reverse course.