For a device meant to represent the future, Klaus Lackner’s mechanical “tree” looks more like a 19th-century machine than a 21st-century tool for scrubbing carbon dioxide from the air. Fortunately this prototype, the highlight of a new Science Museum exhibition on removing CO2 from the atmosphere, will be superseded this summer by more elegant commercial versions akin to giant Alexa speakers.
Seeing the original up close brings home how desperate the climate crisis has become. Failure to cut our emissions fast and deeply enough means we need to remove so much CO2 from the atmosphere that using forests alone won’t cut it – we need engineered approaches like this too.
The start of the Our Future Planet exhibition explains the basics of carbon emissions and climate change, and is devoted to natural solutions, featuring tree rings, videos of ancient forests and animations of how lidar can map carbon in trees. But the reason to visit is the eye-opening second half, on the embryonic efforts to use technology to do the same job as trees.
“This is such an interesting area that’s been relatively neglected. It has moved from being a bit of a joke, to a sinister way to get the fossil fuel industry off the hook, through to being, because we’re in such a pickle at the moment, we’d be mad not to do it,” says Roger Highfield at the Science Museum.
Alongside Lackner’s 2017 tree is an SUV-sized machine resembling a cross between a jet engine and an air-con unit, made by Swiss firm Climeworks. Although the technology is slightly different to the mechanical tree, both use sorbents to absorb the low-level amounts of CO2 in the air. The unit is a bit bigger than some that Climeworks is now deploying, but serves as a reminder of how much infrastructure we will need to build to reach goals of net-zero emissions.
Visitors can see the white threads of CO2 in a cylinder of the basalt rock that Climeworks is using to store CO2 captured in Iceland, plus products made with captured CO2, from vodka to a yoga mat. There is also rock dust, which some researchers think should be sprinkled on farmland to speed up the rate that rocks naturally soak up CO2. Carbon capture and storage (CCS) at heavy industry gets a brief video.
The exhibition explains why such engineered approaches will be needed in addition to the natural ones. There is only 0.9 billion hectares for more trees according to one controversial estimate, plus the sheer scale of our emissions means we need all the methods we can get.
Curator Sophie Waring says she was aiming for “measured optimism”, and isn’t trying to suggest CO2 removal technologies are heroic or will save us. “This has to sit alongside CO2 reductions,” she says, adding that CO2 removals will be best for hard-to-abate industries.
The exhibition mostly gets the balance right between pessimism and optimism, although it could have gone further in showing how expensive and small scale this stuff is. Direct air capture of CO2costs an eye-watering £600-plus a tonne. And all the world’s CCS facilities to date have only captured 260 million tonnes of CO2 – less than the UK emits in a year.
Nonetheless, this is an intelligent, thought-provoking and timely show. Our Future Planet provides a glimpse of objects and technologies alien to most of us today, but likely to become as familiar as old-fashioned trees if we are to successfully tackle the climate crisis.
The Our Future Planet exhibition opens on 19 May at the Science Museum, London.
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