Climate documents spark rich vs. poor clash

Developing nations who face huge climate change burdens are demanding that wealthy nations shoulder more of the costs, as a leaked Danish document and fresh evidence of a hotter planet raised temperatures at the U.N. climate conference.

Negotiators on Wednesday were trying to bridge the difficult gaps among 192 nations and stem a growing chasm between rich and poor on the third day of the U.N. climate conference.

A key speaker will be U.S. Environmental Protection Agency head Lisa Jackson, whose agency just gave President Barack Obama a new way to cut back on greenhouse gas emissions. Obama will join more than 100 national leaders converging on Copenhagen …