In 2015, world leaders in Paris put great hope in keeping the rise in average global temperatures at or below 1.5C. But global temperatures continue rising relentlessly. The world is now on the brink of overshooting the 1.5C target, and then – what? The hope was to stop pumping out CO2 and also remove it from the atmosphere to avoid a cataclysm, but that would need 400 gigatonnes of CO2 to be removed by 2100, using new and as yet untested technology on a vast and economical scale.
A recent report shows that even temporarily overshooting 1.5C will still allow climate change to build up over the next several decades. And that means severe storms, intense heatwaves, deluges of rain and many other disastrous outcomes will carry on increasing.
Even assuming carbon can be removed on a gigantic scale, impacts such as a total collapse of the Greenland ice sheet, melting permafrost, dieback of the Amazon rainforest, and rising sea levels may all reach the point of no return. Keeping 1.5C in check was an overconfident target, but the longer the world spends in overshoot, the greater the risk of inflicting vast damage across the globe.
Jeremy Plester