In the Paris Agreement, nearly 200 countries set their own national targets for reducing or controlling pollution of heat-trapping gases. It was negotiated in 2015 with lots of prodding by the US and China and went into effect on November 4, 2016.
Bernie Sanders, who has energised liberals and young voters, sought to pull away from the rest of the field, while Joe Biden hoped to ride a wave of momentum and endorsements to cement himself as the standard-bearer for the party’s moderate wing.