Enhanced Rock Weathering: A Promising Solution for Carbon Removal
For decades, farmers and gardeners have been using lime, volcanic ash, and crushed stone dust to enhance soil quality. Recent research has shown that this practice, known as enhanced rock weathering (ERW), could play a significant role in removing carbon dioxide from the atmosphere if widely adopted by farmers. In fact, the winners of the $100 million XPRIZE for Carbon Removal utilized ERW to demonstrate its potential for gigaton-scale carbon removal.
A 2020 study by the University of Sheffield revealed that layering soil with calcium- and magnesium-rich ground rock could capture enough carbon to contribute between 5% and 10% of the United States’ annual carbon reduction goals for 2030. In India, ERW could potentially capture and sequester up to 40% of the nation’s Paris Agreement obligations.
Enhanced Rock Weathering involves using rocks such as basalt and limestone to capture CO2 from the atmosphere. As water interacts with these rocks, carbon is dissolved and stored in a hydrogen carbonate solution, which then flows into the groundwater. The process enhances the natural carbon capture capabilities of rocks and increases the amount of CO2 that can be sequestered in the soil.
Field trials conducted in the U.S. Corn Belt have shown that crushed rock can remove three to four metric tons of atmospheric carbon dioxide per hectare per year while also improving crop yields. The practice of ERW not only benefits soil health but also enhances crop production.
Commercial development and industry growth in the ERW sector are on the rise, with companies like Microsoft and British Airways investing millions of dollars in carbon credits based on future emissions reductions. In January 2025, the world’s first verified enhanced rock weathering carbon credits were issued, signaling a significant step toward scaling up this carbon removal strategy.
The Carbon Business Council’s policy primer suggests that ERW prices could decrease to under $100 per ton, making it a more cost-effective solution for carbon removal. With the potential to significantly contribute to global carbon reduction goals, enhanced rock weathering shows promise as a sustainable and effective method for combating climate change.
Mati Carbon, the winner of the XPRIZE Carbon Removal competition, is revolutionizing the fight against climate change by developing systems to deploy rock dust in smallholder farms across countries in the Global South. These countries include India, Tanzania, and Zambia, where agriculture plays a crucial role in the economy and livelihoods of millions of people.
One of the key technologies Mati Carbon is utilizing is Enhanced Rock Weathering (ERW), which involves spreading rock dust on fields to capture and store CO2 in the ground for millennia. This method has the potential to have a long-lasting positive impact on reducing carbon emissions, unlike some other carbon removal strategies like direct-air capture. A study published in Environmental Science & Technology in 2024 emphasizes the importance of environmental monitoring to understand the potential consequences and benefits of scaling up ERW.
Countries like China, India, and Brazil, which are among the top carbon emitters, could significantly reduce their CO2 emissions and meet a substantial portion of their Paris Accord goals by implementing ERW. Furthermore, ERW could be a feasible option for individuals to contribute to carbon removal efforts at home.
Small farms, especially in developing economies, are ideal candidates for ERW programs, as they can serve as effective carbon sinks. This raises the question of whether gardeners could also play a role in fighting climate change by incorporating rock dust supplements like milled basalt or azomite volcanic ash into their gardens annually.
While there is no scientific evidence that home gardeners can directly impact climate change through ERW, there is anecdotal evidence of the benefits of soil augmentation. Small changes made by individuals, when combined on a global scale, can have a significant impact on reducing carbon emissions. The long-term carbon sequestration ability of ERW makes it a promising solution for sustainable carbon removal.
Gardeners with large yards or gardens could potentially enhance their carbon sequestration efforts by adding rock dust supplements to their soil. By improving soil health and root systems, these supplements could help sequester more CO2 from the atmosphere over time.
In conclusion, Mati Carbon’s innovative approach to carbon removal through ERW presents a promising solution for addressing climate change. By exploring the potential of rock dust supplements in home gardens and farms, individuals can contribute to the global effort to reduce carbon emissions and create a more sustainable future for the planet.
