Associated Press: Small island nations gained North America’s powerful backing Tuesday for a plan to convert the U.N. ozone treaty into a tool for phasing out some of the globe’s most powerful climate-warming gases. The Obama administration announced the United States, Canada and Mexico now support using the treaty to require cuts in powerful greenhouse gases known as hydrofluorocarbons, or HFCs. The treaty, called the Montreal Protocol, was signed by 195 nations to fix the globe’s ozone …