New York Times: At the Earth Summit in Rio de Janeiro 23 years ago, the worlds nations adopted a treaty that pledged, but ultimately failed, to cut the emissions driving global warming. In Paris over the last two weeks, negotiators from around the world met for the 21st time since then in an effort to move from aspiration to action. At the Earth Summit in Rio de Janeiro 23 years ago, the worlds nations adopted a treaty that pledged, but ultimately failed, to cut the emissions driving global warming. In Paris...