What if scientists could turn back the clock on greenhouse-gas emissions – just a little? A new process could lock carbon dioxide below the ocean floor, allowing valuable time to reduce the atmospheric greenhouse gases driving climate change.
In 2024 a Solid Carbon pilot at Cascadia Basin off Canada’s Vancouver Island will set out to prove gigatons of captured carbon dioxide can be stored permanently as rock within the subsea floor. Scientists in Iceland have already shown carbon dioxide can be turned into rock: when they injected dissolved carbon dioxide into basalt, the carbon dioxide mineralised – turned to rock – within two years. The Solid Carbon process will work by capturing carbon dioxide from industry, or extracting it from the atmosphere using direct air capture technology, and injecting it into basalt that lies tbelow a thick layer of sediment deep on the ocean floor. There the carbon dioxide will bind with dissolved basalt minerals – calcium, magnesium and iron silicates – and transform into carbonate rock. Up to 800 metres thick, the sediment will keep a lid on the carbon dioxide and allow time for the basalt to react and the transformation to take place. Geochemical simulations by the Solid Carbon team indicate gigatons of carbon dioxide can be stored when plumes of carbon dioxide are injected into deep-ocean basalt. The next challenge is to prove the process works outside the lab. A permanent injection structure will provide an initial demonstration at Cascadia Basin. Once the process has been shown to work, the structure could make continuous injections over a set time.
