PBS: GWEN IFILL: We look more closely now at President Obama`s China meetings in two parts.
First, secret talks began months ago that led to that historic agreement between the two countries on cutting greenhouse gases. But, today, there are still plenty of questions about how it will play out here, in China and globally and whether either side will be able to deliver on its pledges.
Michael Oppenheimer is one of the many authors of the U.N. reports on climate change and a professor of geosciences...