The world’s biggest carbon-sucking machine is switching on in Iceland

We have to start removing carbon dioxide from the atmosphere to have any chance of averting the worst impacts of global warming, the Intergovernmental Panel on Climate Change said last month.

The fossil fuel economy must be run in reverse, effectively. The simplest and lowest-cost way to do that—planting trees—requires a lot of land relative to the scale of intervention that’s needed. So a handful of companies have been tinkering with “direct air capture” (DAC)—essentially, big CO2-sucking machines.