In the UK, the 26th UN Climate Change Conference has opened in the city of Glasgow, Scotland. World leaders are expected to review overall progress and plan future actions on climate change in the coming two weeks. During the G20 summit in Rome, the world leaders pledge to take urgent steps to reach the goal of limiting global warming to 1.5 degrees Celsius. They have also committed to the goal of reaching net-zero emissions "by or around mid-century." Guan Dabo, a professor at Tsinghua University, talks about how these goals can be achieved.