Enhanced Weathering (EW) is an increasingly recognized technological approach to combat climate change by accelerating natural geological processes that capture atmospheric carbon dioxide (CO2). This method involves spreading finely crushed silicate rocks, such as basalt, onto agricultural lands. As these rock particles break down, they react with CO2 and water, forming stable carbonates that effectively sequester carbon for extended periods.
A February 2025 study projected that the widespread implementation of EW within U.S. agriculture could lead to the removal of 160 to 300 million metric tons of CO2 annually by 2050, a substantial contribution towards the nation's net-zero emissions targets. This strategy aligns with the growing understanding that carbon dioxide removal (CDR) technologies are crucial for limiting global temperature increases, as highlighted by international reports such as the IPCC. While olivine was initially explored for its weathering properties, concerns regarding its potential toxicity have shifted the focus towards basalt. Basalt, though weathering at a slower pace, is considered a safer alternative for both soil and water ecosystems.
Furthermore, basalt offers additional agricultural benefits; its slow release of essential nutrients like calcium, magnesium, and iron can improve soil health and fertility. Trials in India have shown that basalt application can lead to notable increases in crop yields, with some studies indicating up to a 20% improvement in tea yields. This dual benefit of carbon sequestration and agricultural enhancement positions EW as a promising tool for sustainable land management.
The application of EW is not limited to specific regions. In the U.S., agricultural lands, particularly in the Corn Belt states, are seen as ideal for EW adoption due to their extensive areas and existing infrastructure. Companies like Vesta and UNDO are actively involved in deploying EW, collaborating with farmers to integrate crushed basalt into their soil management practices. Globally, initiatives like Alt Carbon in India are pioneering the use of EW on tea estates, demonstrating yield improvements and carbon removal simultaneously. These efforts are gaining traction, with agreements from entities like Frontier supporting the scaling of these climate solutions.
The economic viability of EW is also a key factor in its growing adoption. While initial costs may be higher, projections suggest that by 2050, the cost of EW could decrease to approximately $100-$150 per ton of CO2, making it a competitive carbon removal strategy compared to others like direct air capture. This cost-effectiveness, combined with the significant environmental and agricultural co-benefits, underscores the potential of enhanced weathering to play a vital role in a sustainable future.