Russian planes struck targets in western Syria today with almost no warning to the United States. Presidents Obama and Putin have different visions of how to end Syria's civil war. Although both are opposed to ISIS, Russia's strikes appear to be aimed at helping Bashar al-Assad. Are Russian airstrikes in Syria a challenge to the United States?
Also on the program, the world's worst polluters are promising major reductions in advance of the climate-change summit in Paris. But even if they could all make good on all their pledges, global warming would still be catastrophic. We hear about progress made, and what more needs to be done.