We face the gravest threat that civilization has ever confronted. It's global in nature and requires a global solution. Increased CO2 emissions anywhere, whether from China or the United States or from one of the countries that is burning its forests like Brazil or Indonesia.

When energy prices go up, the difficulty of projecting demand also goes up - uncertainty goes up.

We're putting 70 million tonnes of pollution into the atmosphere every day, trapping an enormous amount of extra heat from the sun inside the earth's atmosphere. It's threatening to push the planet past a tipping point beyond which climate change would be difficult to stop

Airplane travel is nature's way of making you look like your passport photo.

When it comes to climate, we can all make a big difference. At the most basic level, don't let denial go unchallenged and win the conversation on climate.

There is no doubt that the issue of race is always present in American politics and in the politics of any multiracial society. There is also no doubt that for some people it is an element in the manifested hostility to Obama. But I don't think it is the major theme at all. Obama is right when he reminds people: By the way, I was black before the election.

As human beings, we are vulnerable to confusing the unprecedented with the improbable. In our everyday experience, if something has never happened before, we are generally safe in assuming it is not going to happen in the future, but the exceptions can kill you and climate change is one of those exceptions.