Could Green Sand Help Us Stop Climate Change?

NEWS | October 5, 2020

Olivine, a green-tinted mineral, absorbs carbon dioxide. One ambitious NGO seeks to spread mass quantities of it across our beaches in order to halt the production of greenhouse gases.

Initiatives that seek to reduce our impact on the o-zone layer have multiplied throughout the past few years. Among them, one American startup has developed an idea that's as unexpected as it is promising. Project Vesta, founded in 2019, aims to spread "green sand" across already-existing beaches in order to soak up CO2 in the ocean and transmute it to a more benign form. The substance in question? Olivine, a cheap volcanic mineral that can be found on Reunion Island and in Hawaii. Oh, and it just so happens to be jade green.  

The emerald dust works thanks to what's called ‘forced alteration.' The method consists in reproducing — and accelerating — the natural process by which volcanic rock dissolves in contact with water, at which point atmospheric carbon dioxide transforms into sediment. By the same process, olivine is distributed along the coast and reduced to powder by the tides. The resulting mineral, rich in silica and magnesium, absorbs CO2 in the atmosphere and turns into bicarbonate. The series of transformations ends with the formation of calcium, which then spreads across the ocean floor.

Some scientists have nonetheless expressed hesitations about "green sand," citing a few concerns. In theory, for example, an increase in silica could also create a proliferation of phytoplankton, which in turn would create anoxic zones, or areas without oxygen. The founders of Project Vesta have thus committed to paying special attention to olivine's early effects on marine ecosystems.  

The startup has recently raised 1.5 million euros to run large-scale field studies on two beaches in the Caribbean. Their hope (and ours as well!) is that by covering only 2% of the planet's beaches in olivine, the totality of human C02 emissions could be safely neutralized and recycled. 