CANCUN, Mexico Related stories: Pages 6, 9 — Japan found itself in unfamiliar territory at the just-concluded U.N. climate change conference in Mexico, having been cast as a major villain that blocked progress as delegates sought to strike a deal on new steps to curb global warming.

The thorniest issue during the 13-day conference, which wrapped up with a better-than-expected outcome in the early hours of Saturday, turned out to be a dispute between Japan and developing countries over the future of the Kyoto Protocol.

Developing countries wanted to continue to see developed countries committed to reducing greenhouse gas emissions under the binding instrument beyond 2012, when its current five-year reduction obligation period expires.