Sliced: Enhanced Rock Weathering - A Growing Climate Solution

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For those following carbon markets, you might have noticed a lot of movement lately around an emerging carbon credit type – Enhanced Rock Weathering (ERW).

ERW is a rapidly growing carbon dioxide removal (CDR) technique that mimics and accelerates natural geological processes. By spreading finely crushed silicate rocks, such as basalt or olivine, on farmland, ERW captures atmospheric carbon dioxide (CO2) through chemical reactions with rainwater. These reactions form stable bicarbonate ions that are eventually transported into oceans or retained in soils, storing carbon for thousands of years. This method reduces atmospheric carbon while improving soil health, boosting crop yields, and reducing the need for synthetic fertilizers – creating significant agricultural co-benefits.

In the context of carbon markets, ERW has gained traction due to its durability and potential for large-scale deployment. With an estimated storage permanence of over 10,000 years and the ability to integrate into existing agricultural infrastructure, ERW represents a cost-effective solution for climate mitigation. Its average removal cost ranges between $50–$200 per ton of CO2 which makes it more affordable than many direct air capture methods. Moreover, the co-benefits to soil quality and crop productivity further enhance its economic viability, especially in regions dependent on agriculture.

ERW also has strong potential for rigorous monitoring, reporting, and verification (MRV). Methodologies like Isometric’s Enhanced Weathering Methodology mandate direct soil and porewater analysis to measure CO2 uptake and safeguard high data fidelity. This scientific rigor is critical in the carbon credit world, where transparency and accountability determine the credibility and traceability of credits. Some projects even use industrial byproducts like steel slag as a rock source which can maximize the circular use of materials while minimizing the environmental footprint.

The first verified ERW carbon credits were issued in January 2025 by InPlanet in collaboration with Isometric. Their project in Brazil employed soil chemistry to validate CO2 removal. These credits were purchased by Dutch fintech firm Adyen, with credit prices ranging from $300 to $400 per ton. The high price reflects the quality and permanence of the removal, as well as the stringent verification process – a sign that ERW is being taken seriously in premium carbon markets.

Corporate investment has been a major driver of ERW’s recent momentum. Google, for instance, made headlines with its $33 million offtake agreement with Eion Carbon to purchase 79,000 tons of carbon credits by 2030, alongside a record-breaking 200,000-ton commitment to Terradot. Microsoft has also entered the ERW space through a partnership with UNDO, aiming to remove 15,000 tons of CO2 using crushed basalt. These collaborations mark a shift from experimental research to real-world application, with tech giants effectively de-risking early-stage climate technologies.

The scientific and agricultural communities are also contributing to ERW’s growth. The UK’s Enhanced Rock Weathering Demonstrator Project is testing ERW across multiple agricultural sites to provide insights into regional deployment and inform net-zero strategies. Meanwhile, companies like Eion are conducting deep soil core studies in the United States. to refine their understanding of CO2 sequestration dynamics and improve future MRV protocols. These efforts reflect a growing consensus that ERW is not only a viable CDR tool but also a valuable source of environmental data and innovation.

Investment in ERW startups has surged, with more than $300 million committed since late 2024. This influx of climate finance is largely fueled by corporate sustainability goals and the demand for high-quality, durable carbon removal solutions. ERW is now positioned alongside other nature-engineered carbon removal methods like biochar and soil carbon sequestration, forming a diverse portfolio of tools to combat climate change. Its unique blend of geological science and agricultural integration makes it especially attractive in both developed and emerging economies.

Despite the momentum, challenges remain. Standardizing MRV protocols across geographies, reducing costs for broader farmer adoption, and ensuring equitable access to ERW benefits are ongoing concerns. Still, the combination of scientific validation, corporate backing, and ecological benefits positions ERW as a potential cornerstone of durable carbon removal.

As nations and industries strive toward net-zero targets, ERW is starting to stand out for both its climate impact and for its potential to transform the way we manage land, soil, and atmospheric carbon.