By Paul Davies and Michael Green

Prior to the G20 Leaders’ Summit on 4 September, China and the US ratified the Paris Climate Agreement during a ceremony in Hangzhou, China. This commitment from the world’s largest carbon dioxide emitters is expected to prompt developed nations in Europe to follow suit.

The adoption of the Paris Agreement by 195 countries is widely considered to be one of the most ambitious international environmental agreements, whereby parties committed to limiting the increase in the global average temperature to 2˚C above pre-industrial levels while striving to limit the temperature increase to 1.5˚C.

China and the US join 25 other signatories who have ratified the Paris Agreement – the majority of whom are islands particularly vulnerable to climate change, for example, the Bahamas and Nauru. With China and the US now among the signatories, it is likely to accelerate the entry into force of the Paris Agreement.