An effort by Australia and the United States to forge a new post-Kyoto consensus on how to tackle climate change ran into opposition from China on Thursday.

This summer the cardinals at the Vatican accepted an unusual donation from a Hungarian start-up called Klimafa: The company said it would plant trees to restore an ancient forest on a denuded island by the Tizsa River to offset the Vatican's carbon emissions.

Energy-saving opportunities in American homes are immense with current technology, but new product standard mandates will be needed, according to a study by the McKinsey Global Institute.