The necessity of pulling carbon dioxide out of the air

OF THE WISDOM taught in kindergartens, few commandments combine moral balance and practical propriety better than the instruction to clear up your own mess. As with messy toddlers, so with planet-spanning civilisations. The industrial nations which are adding alarming amounts of carbon dioxide to the atmosphere—43.1bn tonnes this year, according to a report released this week—will at some point need to go beyond today’s insufficient efforts to stop. They will need to put the world machine into reverse, and start taking carbon dioxide out. They are nowhere near ready to meet this challenge.Once such efforts might have been unnecessary. In 1992, at the Rio Earth summit, countries committed themselves to avoiding harmful climate change by reducing greenhouse-gas emissions, with rich countries helping poorer ones develop without exacerbating the problem. Yet almost every year since Rio has seen higher carbon-dioxide emissions than the year before. A staggering 50% of all the carbon dioxide humankind has put into the atmosphere since the Industrial Revolution was added after 1990. And it is this total stock of carbon that matters. The more there is in the atmosphere, the more the climate will shift—though climate lags behind the carbon-dioxide level, just as water in a pan takes time to warm up when you put it on a fire.