should all stand above partisan politics and be together on this challenge. >> christiana, you say it is a human challenge. the pope has said the environment has its own intrinsic rights. we're all part of the environment. and you talk about how maybe opponents may be shifting opinions. and right now the president of china xi jinping is coming to the white house and he is in the u.s. and there are reports he is going to announce major advances in what china will do to cap emissions. and he's already stated there is going to be progress by 2030. how important is that? because in the end it is about political will of the world leaders. particularly china and india, the others, to get together on this issue. >> a absolutely. and the announcement that will be made by china and the united states, it would not surprise me if what they bring forward are details about how they will individually, but also collectively, implement the very