Three months ago, the Obama administration made a little-noticed but potentially pivotal move in the stepped-up fight against climate change: it boosted the U.S. government's official estimate of the future economic damage caused by carbon pollution. The move should make it much easier for the EPA and other federal bureaus to enact tougher measures to crack down on emissions by showing that the greater benefits of such measures will justify their costs. "This has all the characteristics of a stealth approach toward making a greenhouse gas rule more justifiable by exaggerating the social benefits," said Luke Popovich, a spokesman for...