In the future, environmentally responsible travellers might be sunbathing on green instead of white sand beaches, which help remove CO2 from the atmosphere. Erica Jamieson reports
Green sand beaches made of ground-up olivine (a volcanic mineral) may accelerate a naturally occurring carbon capture process that could slow global climate change.
It may sound like science fiction, but there are already a handful of green sand beaches in the world such as the one pictured here, on Big Island in Hawaii. There is also one in Guam, Norway and the Galapagos Islands.
Project Vesta, the nonprofit behind the olivine beach initiative, will soon commence a pilot project to demonstrate this in the Caribbean. It estimates that olivine sand would need to cover just 2 per cent of global shelf seas to capture 100 per cent of annual human carbon emissions. Olivine, which makes up about half of the earth’s upper mantle, comes from the same family of rocks as the common gemstone peridot.
Typically, rainwater erodes olivine deposits on land and carries mineral fragments to the ocean, where a reaction with seawater draws CO2 from the air. Over billions of years, this process has transformed olivine into a hydrocarbonate product that forms seashells and coral, and eventually becomes limestone.
Project Vesta hopes to harness wave action to accelerate this process. Olivine will be mined from nearby deposits and ground into sand to increase surface area, which can be spread over beaches. The nonprofit claims that olivine ocean erosion captures 20 times more carbon dioxide than extraction and transportation, and costs only US$10 per ton of carbon captured.
The weathering process also reduces ocean acidification, which may benefit marine life.
Established in 2019, Project Vesta grew from a think tank called Climitigation. Similar projects have been theorised in the past but practical pilot demonstrations are a first.
“About 30 years of scientific research has gone into this, including a lot of theoretical work, a lot of lab experiments,” says Tom Green, executive director of Project Vesta, in Fast Company. “Where we came along was to say, why is this stuck in the lab? We need real-life beach experiments to prove that this actually works in the wild… We exist to cross that chasm between the world of academia, which was doing a lot of theoretical experiments, and ultimately, the government and privately funded roll-out.”
Early funders include Stripe, the credit card processing company, and other private donors, as the nonprofit works to raise US$1.5 million for continued experiments. In the long term, Project Vista plans to use green sand beaches to help entire nations reach carbon neutrality, on a global scale.
“Reducing emissions is not enough to solve the climate crisis,” stated Project Vesta co-founder, Eric Matzner. “We need a solution that removes gigatons of carbon dioxide emissions a year and we need it now. Once we prove our approach through pilot studies, we can implement at scale through an open-source platform.”
Some critics have raised concerns that increased levels of olivine on beaches could release heavy metals, such as nickel, into the water. The upcoming pilot project will closely monitor metal concentrations in the water, sand, and tissues of local organisms, to measure this impact.
If successful, green sand could be an effective alternative to planting forests, which have recently been criticised for “doing more harm than good“. According to the BBC, one study has shown that financial incentives to plant trees can backfire and reduce biodiversity with little impact on carbon emissions, while another found that the amount of carbon that new forests can absorb may be overestimated.
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