EcoWatch: Hillary Clinton may be the prohibitive favorite, and the Democratic slate for the presidential nomination almost certainly wont be as large as the Republican field. But Saturday, another credible candidate joined Clinton and Vermont Sen. Bernie Sanders in the race: former Maryland Governor Martin OMalley, who left office in January after serving for eight years. And, like Clinton and Sanders, those who care about the climate will find him a more sympathetic candidate than anyone on the GOP side....