It sounds too good to be true — spread some rocks on a beach and the ocean will do the work to remove carbon dioxide from the air, reversing global warming. But that’s a very simplified explanation of what Project Vesta hopes to accomplish. The idea is to accelerate a natural process. When rain falls on volcanic rocks, it weathers them down, then flows into the ocean. There, oceans further break down the rocks. Carbon dioxide removed from the air becomes bicarbonate, which helps grow the shells of marine organisms and is stored in limestone on the ocean floor.

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close-up of green sand on a beach

Project Vesta wants to speed up this process by grinding up olivine — a common, gray-green silicate that weathers quickly — and spreading it on beaches and in shallow shelf seas around the world. It has worked in a lab, but will it work in the real world? We’re about to find out, as Project Vesta is now preparing a pilot beach in the Caribbean.

Related: Demand for sand — the largest mining industry no one talks about

hand holding sand mixed with ground olivine

Origins of Project Vesta

Project Vesta has rounded up an international crew of scientists, environmentalists, futurists and financial experts since its founding on Earth Day 2019. The not-for-profit organization sprang from a think tank called Climitigation, Project Vesta executive director Tom Green told Inhabitat. “It’s very clear at this point that in order to avoid the worst effects of global warming, reducing emissions will not be enough,” Green said. “Maybe 20 years ago that would have been a viable path. But at this point, even though we should reduce emissions, that on its own will not be enough to avoid the worst scenario.”

Climitigation examined different ways to reverse global warming, prioritizing them according to their viability. The idea of coastal weathering came to the top, Green said, “as being potentially very, very cheap, very scalable, a permanent carbon catcher, with relatively little attention that had been paid to it so far. So Project Vesta was founded out of that think tank, and we exist to further the science of enhanced weathering ultimately to galvanize global deployment that will help reverse climate change.”

The idea of coastal weathering has 30 years of academic research in the fields of biology and geochemistry behind it. But it had stalled out, unable to cross the financial chasm from academic to mainstream, said Green, who trained as a biologist before spending 20 years in business at various tech companies. “Nobody had come along and said, ‘Okay, I’m going to push this forward.’ That’s what we’re here to do.”

waves crashing on a beach with green sand

The pilot beach

Scientists at Project Vesta had a set of criteria for finding the right pilot beach. “We scoured the world for an ideal site,” Green said. “This initial site that we found is great for our pilot beach site. It’s a fairly enclosed cove, which means the water has a pretty low refresh rate. Which means that as the chemical reaction happens, there’s enough time for the biogeochemical indicators to change before the water gets washed away into ocean.”

In a few months, after thoroughly measuring the test cove, Project Vesta will cover the pilot beach with ground olivine. Then comes the monitoring phase. Scientists will sample water and sand, measuring indicators like DIC, or dissolved inorganic carbon, which directly measures the amount of carbon in the water.

“These indicators are designed to measure the speed of the reaction that’s happening and actually look at the carbon as it is being removed from the atmosphere,” Green explained. “On the biological side, we’ll also be measuring the prevalence of various species that are there, both macroscopic and microscopic species, and looking at any changes in that as the experiment proceeds.” A nearly identical cove less than a quarter mile away will serve as a control cove.

One concern is whether olivine could release nickel or other heavy metals into the water. Green told Fast Company that this nickel won’t be bioavailable, so it won’t harm marine species. But the pilot study will monitor metal concentrations to assess the real life impact to sand, water and local marine organisms.

In addition to removing carbon dioxide from the atmosphere, Project Vesta hopes that more green beaches will reverse the ocean’s rising acidity. “The reaction that happens when olivine dissolves actually makes the ocean less acidic,” Green said. “Ocean acidification is a major problem and is causing problems for a lot of species. It’s very clear that doing this will reduce acidity at the site where it’s done. And then there’s a hypothesis that that will actually be beneficial for local marine ecosystems. But we don’t know that yet for sure. We need to test it out.”

Green beaches could also be a tourism draw. Papakolea on Hawaii’s Big Island is the world’s most famous green sand beach. It does more than alright for itself, tourist-wise.

diagram explaining Project Vesta's plan to use green sand to absorb carbon

Future green beaches

The Project Vesta folks hope that they’ll see a positive impact on their pilot beach within a year. If it’s successful, they’ll work with interested governments to expand the project. Green anticipates that members of the V20 — countries especially susceptible to climate change — may be especially receptive to green sand beaches. Island nations with lots of shoreline will be top candidates.

If all went perfectly, how long would it take for green sand beaches to reverse climate change? Project Vesta scientists estimate they’ll need to dump ground olivine in 2% of the world’s shelf seas — the shallow coastal waters surrounding every continent — for the plan to work. “The scale of the problem is so big that any solution will also be largescale,” Green said.

Project Vesta plans to find local or nearby sources of olivine to save financial and carbon costs of transporting the green rock. Even when factoring in the mining and transportation, the project claims it can capture 20 times the carbon it takes to make a green sand beach.

Moving all these rocks will cost money. The credit card processing company Stripe is one of the project’s backers, in keeping with its pledge to spend $1 million a year on carbon removal technologies. Individuals can make donations of any size on Project Vesta’s website or support the project by buying a Grain of Hope necklace for $25. Fittingly, the jewelry sports a single grain of olivine suspended in a sand timer vial, symbolizing that time is running out on reversing climate change.

+ Project Vesta

Images via Project Vesta

beach with green sand on a sunny day