The US is getting "greener" as coal is replaced by natural gas, which is cleaner and cheaper, but that doesn't mean the coal industry's going away. Its salvation might lie in exports. Massive coal deposits on federal land in Wyoming and Montana have already been leased to companies with plans for export to China. That's created furious opposition to mile-long coal trains and entire new ports proposed for construction on the Pacific coast. What would it mean for local pollution and global warming? Will the principal benefits go to the public or the coal industry?