With each month that passes, a solar panel gets 2 or 3 percent cheaper. So while we're holding the fossil fuel industry in check, the engineers in the renewable energy world are undercutting them from the other side.

All the science in the last few years, or almost all of it, really serves to show that the [climate] effects are larger and more rapid than we had thought even a decade ago.

I do a certain amount of work in religious communities on these issues. It's not the central focus of my work but it is certainly an area where I have worked a lot. It has gotten much better over the years, especially over the last couple years. There wasn't a religious environmental movement 15 years ago, but there is now - in the Catholic community, the Jewish community, the mainline Protestant community, and in the Evangelical community.

By themselves, they are not enough; we also need to engage in political action.

I'm guessing the most efficient way would be to transfer an awful lot of technology, but also direct aid to deal with climate emergencies already underway. Hillary [Clinton] has already said $100 billion a year would be appropriate.

I think communities of faith are extremely important in this question. I think that all faith communities share a common and unusual distinction in our time of being the only institutions left that can posit some goal other than accumulation for human existence. I think that's enormously important because it is that drive for consumption more than anything else that fuels the environmental devastation around us.

Global warming is no longer a philosophical threat, no longer a future threat, no longer a threat at all. It's our reality.