1.5°C is slipping away. What now?

The United Nations Environment Program says the world is set to exceed the 1.5-degree Celsius warming limit within the next few years, making some degree of overshoot unavoidable. What happens once we cross that threshold? Can global temperatures eventually be brought back down? Climate Watch host Zhao Ying speaks with Professor Teng Fei, deputy director of the Institute of Energy, Environment, and Economy at Tsinghua University.