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."

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.

Yet again, unscientific claims were being circulated broadly, but the scientists' refutation of them was published where only fellow scientists would see it.

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.

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.

We don't survive without plants and animals because we rely on them, we rely on plants to put oxygen into the atmosphere, we rely on ... fish and crops and cows to eat.

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