First test of CO2 removal with green sand finds no harm to marine life

A beach in Southampton, New York, treated with olivine sand The first trial to absorb atmospheric carbon dioxide by adding crushed olivine to the ocean had no adverse effects on the seafloor ecosystem in its first year. While the results of the trial in New York state are promising for this carbon-removal technique, researcherss warn they may not have captured all potential negative impacts. The addition of olivine to the ocean should still be carefully regulated, “but there might be ways that i

The United Nations climate body has said the world will need carbon removal methods , which range from planting trees to filtering out CO2 from the air with giant machines, to reach net-zero greenhouse gas emissions. As emissions continue to rise and the goal of limiting global warming to 1.5°C above preindustrial levels slips out of reach, many hope these technologies could someday help cool the planet back down. Olivine, or magnesium iron silicate, is a greenish mineral common in Earth’s mantle. Once it comes to the surface, it tends to react with the CO2 dissolved in rainwater to form metals, silicates and bicarbonate, a stable compound that eventually flows into the ocean, locking CO2 away for thousands of years. Spreading crushed olivine and other silicates on farm fields could speed up this process and remove up to 1.1 billion tonnes of CO2 annually, recent research found. But US start-up Vesta plans to add olivine directly to the ocean, where it would turn dissolved CO2 into bicarbonate and allow the ocean to absorb more CO2 from the atmosphere. Olivine typically contains trace amounts of heavy metals, however, and lab studies have found elevated levels of nickel and chromium in crustaceans and molluscs exposed to it. Researchers have also been concerned that the sand could smother bottom-dwellers like crustaceans, molluscs, snails and worms. In 2022, Vesta deposited 650 tonnes of olivine sand along a beach in Long Island, New York state, on top of 13,500 tonnes of regular sand added to bolster the shore, which is being swept away as storms intensify. The tide and waves carried the olivine out to sea. Researchers scooped up sediment from the shallows out to 160 metres offshore before and after the olivine addition and again a year later. They compared this to sediments near sections of the beach where only normal sand was added and where no sand was added.

Key points

• The United Nations climate body has said the world will need carbon removal methods , which range from planting trees to filtering out CO2 from the air with giant machines, to reach net-zero greenh…
• As emissions continue to rise and the goal of limiting global warming to 1.5°C above preindustrial levels slips out of reach, many hope these technologies could someday help cool the planet back down.
• Olivine, or magnesium iron silicate, is a greenish mineral common in Earth’s mantle.
• Once it comes to the surface, it tends to react with the CO2 dissolved in rainwater to form metals, silicates and bicarbonate, a stable compound that eventually flows into the ocean, locking CO2 aw…
• Spreading crushed olivine and other silicates on farm fields could speed up this process and remove up to 1.1 billion tonnes of CO2 annually, recent research found.