Crushed Rock, Big Impact: A Soil-Based Carbon Breakthrough Wins Big

US nonprofit’s soil-based method draws CO₂ into farmland, offering a lower-cost alternative to engineered climate technologies

25 Apr 2025

The $50 million XPRIZE Carbon Removal award went to an idea that is strikingly simple. Crush volcanic rock. Spread it on farmland. Let nature take over.

A U.S. nonprofit won the prize by proving that finely ground basalt can pull carbon dioxide from the air and store it in the soil for the long term. When rain mixes with CO₂, it reacts with the rock and forms solid minerals that stay underground. Scientists call this enhanced rock weathering. Farmers see stronger, healthier soil.

That mix of climate impact and farm benefits is what makes the project stand out. The basalt does not just remove carbon. It also improves soil quality and can increase crop yields. Climate action, in this case, fits easily into everyday farming.

The idea itself is not new. What had been missing was clear proof that it works at scale. Through large trials on rice farms in India, the team showed it could remove more than 1,000 metric tons of carbon dioxide in a single year. Independent experts checked the data and confirmed the results, giving the project rare credibility.

That validation opened doors. The group is now expanding its work in Zambia and Tanzania, with a long-term goal of removing 100 million tons of carbon by 2040. Compared with high-cost machines that pull carbon directly from the air, this approach looks refreshingly low-tech.

“This changes how people think about carbon removal,” said climate tech investor Sarah Kaplan. She believes the win could push more funding toward solutions that work with nature instead of against it.

Nature-based projects have often faced doubt, especially around how long the carbon stays locked away and how well it can be measured. This effort tackled those concerns head-on with strong data from real farms.

There are still challenges. The rock has to be mined, moved, and spread, and the carbon must be tracked over many years. Even so, the promise is clear. By turning farmland into a carbon sink, this method suggests that one of the most practical climate tools may already be beneath our feet.