THE 2015 PARIS CLIMATE CHANGE AGREEMENT ‘committed signatories to do what is necessary to keep global warming “well below” 2°C compared with pre-industrial times by 2100, and preferably closer to 1.5°C. Most scientists agree that if the increase is more than 2°C, there is a serious risk of catastrophically higher sea levels and more floods, superstorms and wildfires like those that have afflicted places from Kolkata to the Caribbean to California this year. Greenhouse gases released by humanity have already warmed Earth by 1°C or so since the 1870s. Because planet-cooking carbon dioxide lingers in the atmosphere for thousands of years, stabilising emissions will not suffice to hit that target. Emissions must fall, and quickly (even into negative territory: carbon dioxide will need to be scrubbed from the air somehow). Instead, they are expected to edge up by 2% in 2017, after three years of near-stability. The Paris deal’s voluntary, flexible nature means that it is national pledges, backed by legislation, that collectively add up to global climate governance,’ (‘New life for the Paris deal’, The Economist 16th December 2017, p51).