Most people have thought of ... climate change as a problem about the environment that is separate and distinct from problems of human wellbeing.

At a recent conference, a colleague told one of us that in IPCC discussions, some scientists have been reluctant to make strong claims about the scientific evidence, lest contrarians "attack us". Another said that she'd rather err on the side of conservatism in her estimates, because then she feels more "secure."

When we damage the environment, we damage everything we depend on.

I think Pope Francis is our Pope Francis. I mean, the point of him is that he's a global leader, and he's trying, I think he's embracing that role.

Scientists should continue doing what they've always done, which is to understand the Earth as well as they can.

Many people have the impression that there is significant scientific disagreement about global climate change. It's time to lay that misapprehension to rest. There is a scientific consensus on the fact that Earth's climate is heating up and human activities are part of the reason. We need to stop repeating nonsense about the uncertainty of global warming and start talking seriously about the right approach to address it.

There's real economic costs to climate change - So, Superstorm Sandy led to billions of dollars in damages. The fires out in the west, 70 million dollars a day are being spent in fighting fires that have clearly been exacerbated by drought and climate change. So, people have pointed out the true dollars and cents cost of inaction on climate change.