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Google and Other Giants Back Terradot’s Enhanced Rock Weathering Strategy
In an effort to counteract the impact of their pollution on the climate, tech giants like Google have invested heavily in a startup called Terradot. This Sheryl Sandberg-backed company has developed a low-tech approach to carbon dioxide removal using enhanced rock weathering (ERW). The strategy involves crushing up rocks and spreading them out over a large area, increasing the surface area of exposed rock that reacts with CO2.
Big Companies Sign Multi-Million Dollar Deals
Google and other big companies have collectively agreed to pay Terradot $27 million to remove 90,000 tons of carbon dioxide from the atmosphere. This deal was brokered by Frontier, a carbon removal initiative led by Stripe, Google, Shopify, and McKinsey Sustainability.
Separately, Google has announced its own deal with Terradot to purchase an additional 200,000 tons of carbon removal. While the company declined to disclose the cost of this deal, it is estimated that if the price is similar to the Frontier agreement ($300 per ton of CO2 captured), it could add up to $60 million.
Enhanced Rock Weathering: A Low-Tech Tactic for Carbon Removal
Enhanced rock weathering attempts to speed up a natural process that might take thousands of years. Rainfall naturally ‘weathers’ or breaks down rocks, releasing calcium and magnesium and triggering a chemical reaction that traps CO2 in water as bicarbonate. Groundwater carrying that bicarbonate eventually makes its way to the ocean, which stores the carbon and keeps it out of the atmosphere.
Terradot’s ERW strategy involves using basalt from quarries in southern Brazil to nearby farms. Farmers can use the finely-ground basalt to manage the pH of soil, and carbon removal is a bonus. Terradot has partnered with Brazil’s agricultural research agency (EMBRAPA), allowing the startup to use this strategy on over one million hectares of land.
Challenges Ahead: Measuring Carbon Removal
While enhanced rock weathering shows promise as a low-tech tactic for carbon dioxide removal, there are challenges ahead. One of the biggest hurdles is measuring how much CO2 Terradot actually manages to trap.
Google acknowledges this challenge in its announcement: "Right now, it’s hard to measure with precision how much CO2 this process removes from the atmosphere. But the only way to develop highly rigorous measurement tools is to deploy this approach widely in the real world."
Terradot plans to take soil samples to assess how much CO2 is captured based on how the rock degrades over time. However, it’s harder to figure out how much calcium, magnesium, and bicarbonate makes it to the ocean to permanently sequester CO2.
