Enhanced rock weathering: How crushed volcanic rock on farms could remove CO2 from the atmosphere

Enhanced rock weathering is gaining attention as a carbon dioxide removal strategy that works alongside farming. Scientists are spreading finely crushed basalt on agricultural land to speed up a natural process where rainwater and CO2 form a weak acid that breaks down silicate minerals. This reaction converts carbon into stable bicarbonate ions that eventually wash into the ocean and stay trapped for thousands of years. The method uses equipment farmers already have for spreading lime or fertilizer. Beyond capturing carbon, basalt releases nutrients like calcium, magnesium, and potassium into the soil, which can improve fertility and reduce acidity. A study in Science of the Total Environment confirms the potential but notes that field measurements are essential to verify how much CO2 is actually removed, especially in acidic tropical soils where natural soil acids may drive some of the weathering. Challenges remain. Mining, crushing, and transporting the rock requires energy, so the net climate benefit depends on using low-carbon power. Researchers also need reliable verification methods before farmers can earn carbon credits. Still, the approach offers a practical way to link carbon removal with existing agricultural practices.