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.

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

Scientists have been saying, for an awfully long time, that we're all interconnected. Scientists would use the word 'ecosystem' to express that idea. Obviously, people can't survive without air and water, and we rely on plants and animals for food, and plants and animals rely on us to preserve their habitats.

Scientists are scientists. They're not really in a position to speak clearly on the moral dimensions, and they're not really comfortable doing that.

What to do about climate change is political, it's social, and it's moral, which is one of the reasons the scientific community reached out to the Pope, to ask for his involvement in this issue.

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.

It really is a very radical call ... to reject materialism as our central value and to think about the sanctity of life and what that really means if we take it seriously.