The five warmest years over the last century occurred in the last eight years.

I tend to be naive and gullible, I guess, but I try to believe that governments believe what they say.

Politicians think that if matters look difficult, compromise is a good approach. Unfortunately, nature and the laws of physics cannot compromise - they are what they are.

The urgency derives from the nearness of climate tipping points.

Several times in Earth's history, rapid global warming occurred, apparently spurred by amplifying feedbacks. In each case, more than half of plant and animal species became extinct. New species came into being over tens and hundreds of thousands of years. But these are time scales and generations that we cannot imagine.

It would be immoral to leave young people with a climate system spiraling out of control.

The climate system is being pushed hard enough that change will become obvious to the man in the street in the next decade.