Time Magazine: When President Obama hammered out an agreement with leaders of China, India, Brazil and South Africa in the waning hours of the U.N.’s climate-change summit in Copenhagen in December, they saved the long-running global-warming negotiation process from total disintegration. But it may have been just a stay of execution. The U.N. Framework Convention on Climate Change (UNFCCC) gave all nations until Jan. 31 to sign onto the deal — in part because it was opposed by a handful of …