Astronomer Royal Lord Martin Rees on Climate Change

The UN warned of a 3.2 degree Celsius temperature rise by the end of this century – woefully short of the two degree goal stated at the Paris Climate Accord. So will we survive the 21st century? 15 years ago, Britain’s Astronomer Royal Lord Martin Rees gave it a 50/50 chance. Now, he remains doubtful about humanity’s future, and discusses his fears and possible solutions with Christiane Amanpour.