Scientists with access to data from Navy submarines traversing underneath the North polar ice cap have warned that there is now a 75 percent chance that within five years the entire ice cap will completely disappear during the summer months.

Because these consequences are distributed globally, the problem masquerades as a distraction. Because the length of time between causes and consequences stretches out longer than we're used to dealing with, it gives us the illusion that we have the luxury of time. Neither of those things is true.

Fear is the most powerful enemy of reason.

The Internet empowers individuals to play a more active role in the political process, as Obama's campaign has manifested.

The key.. will be a new public awareness of how serious is the threat to the global environment. Those who have a vested interest in the status quo will probably continue to be able to stifle any meaningful change until enough citizens.. are willing to speak out.

I have a personal staff that helps me scour the internet and other media for the latest scientific peer-reviewed findings, the latest examples of climate-related extreme weather events, and the latest examples of progress. The world is in the midst of a sustainability revolution that has the scope of the industrial revolution, but with the speed of the digital revolution. That's not enough without new laws and the right kind of political leadership. But it does give us a base from which to build a movement that will save us from the most catastrophic consequences of the climate crisis.

Anyone who deals with the climate crisis has an internal dialogue between hope and despair, because the challenge is so huge and the danger is so great and the stakes are so high. But I have always resolved that in favour of hope, and actually I'm more hopeful now than I was a decade ago when the solutions were visible on the horizon, but you had to seek reassurance that the technology experts that they're coming, they'll be here.