On the sidelines of the G20 summit in Hangzhou, which came to a close on Monday 5 September, United States President Barack Obama and his Chinese counterpart Xi Jinping made a joint announcement on Saturday 3 September that their countries had ratified the Paris Agreement, sending out a strong signal which the European Union immediately welcomed.
The world’s two largest emitters, who together produce about 40% of greenhouse gas emissions, submitted their instruments of ratification to the...