Last summer, a heatwave baked the entire Northern Hemisphere, killing dozens from Quebec to Japan. Some of the most destructive wildfires in California history turned more than a million acres to ash, along the way melting the tyres and the sneakers of those trying to escape the flames. Pacific hurricanes forced three million people in China to flee and wiped away almost all of Hawaii's East Island.

We are living today in a world that has warmed by just 1 deg C since the late 1800s, when records began on a global scale. We are adding planet-warming carbon dioxide to the atmosphere at a rate faster than at any point in human history since the beginning of industrialisation. In October, the United Nations Intergovernmental Panel on Climate Change released what has become known as its "Doomsday" report - "a deafening, piercing smoke alarm going off in the kitchen", as one UN official described it - detailing climate effects at 1.5 and 2 deg C of warming.