Around the world, dozens of ingenious projects are trying to ‘trick’ the ocean into absorbing more CO2. But critics warn of unforeseen consequences
Tom Green has a plan to tackle climate change. The British biologist and director of the charity Project Vesta wants to turn a trillion tonnes of CO2 into rock, and sink it to the bottom of the sea.
Green admits the idea is “audacious”. It would involve locking away atmospheric carbon by dropping pea-coloured sand into the ocean. The sand is made of ground olivine – an abundant volcanic rock, known to jewellers as peridot – and, if Green’s calculations are correct, depositing it offshore on 2% of the world’s coastlines would capture 100% of total global annual carbon emissions.