Engineers have built machines to scrub CO2 from the air – and it could halt climate change

On Wednesday this week, the concentration of carbon dioxide in the atmosphere was measured at 415 parts per million (ppm). The level is the highest in human history, and is growing each year. Amid all the focus on emissions reduction, the Intergovernmental Panel on Climate Change (IPCC) says it will not be enough to avoid dangerous levels of global warming. The world must actively remove historical CO₂ already in the atmosphere – a process often described as “negative emi