China and the U.S. are the two greatest emitters of carbon, so their environmental and economic policies have the power to either save or destroy the planet. Join us as two of the world’s leading climate thinkers—Jeffrey Sachs, an economist who runs Columbia University’s Center for Sustainable Development, and Ma Jun, founder of the Institute of Environmental Policy and Affairs in Beijing—share insights on what the two nations can do to ensure we get to zero net greenhouse emissions.