How the landmark Paris Climate Agreement came together

Nine years after it was negotiated, the Paris Climate Agreement continues to serve as a blueprint for global environmental goals. Todd Stern, the top U.S. negotiator for the deal, outlines the years-long process it took to reach the landmark agreement in his new book, “Landing the Paris Climate Agreement: How It Happened, Why It Matters and What Comes Next.” Stern joins CBS News to look back at the talks.