Direct action: Carbon capture gears up for climate battle

When humans first started burning fossil fuels on an industrial scale in the late 19th century, Earth’s atmosphere contained about 280ppm of CO₂. The intervening years have seen that concentration rise above 410ppm, alongside a corresponding global average temperature increase of more than 1°C. There is virtually blanket scientific consensus that atmospheric CO₂ is the root cause of this rapid warming, and that humanity must stop burning fossil fuels to halt it. Recently, however, there has also been growing consensus that decarbonisation on its own will not be enough.

If the goals set out in the 2016 Paris Agreement are to be met, many scientists – including those at the Intergovernmental Panel on Climate Change (IPCC) – believe that CO₂ must be actively removed from the atmosphere. There are numerous ways this might be achieved using quasi-natural methods such as large-scale reforestation, rock weathering, and instigating massive ocean algae blooms that act as carbon sinks. Less natural – but no less interesting – is the method of direct air capture (DAC), whereby CO₂ is extracted from the atmosphere using man-made technology.