What Can COP Achieve Without Major Emitters?

From the BBC World Service: The summit is part of an effort to show that the climate crisis remains a top priority, although some big names won't be in attendance, including leaders of China, India, and the U.S. What can the conference achieve without them? Then, China has announced it's easing tariffs and export controls on U.S. firms following last week's seemingly productive meeting between Xi Jinping and Donald Trump. And in Shanghai, foreign businesses are being welcomed to a major trade import expo.