Climate change & mitigation
Enhanced weathering
Definition
Enhanced weathering is a carbon dioxide removal approach that accelerates the natural geological weathering of silicate rocks by grinding them to increase reactive surface area and spreading them on soils, especially farmland. As the rock weathers, atmospheric CO2 is converted to dissolved bicarbonate, which is transported via rivers to the ocean for long-term storage, and may also form stable carbonate minerals in soils.
References
mechanism, storage durability, ~1 billion tonnes natural baseline
Overview
What it means
Natural rock weathering removes on the order of one billion tonnes of CO2 per year; enhanced weathering aims to speed this up while potentially co-benefiting soils (pH correction, nutrient release). The main challenges are quantification and verification of removals, energy use in crushing and transport, and heavy-metal content of feedstocks.
How it is used
Deployed by carbon-removal companies on agricultural land with measurement and verification protocols; assessed in IPCC and academic CDR portfolios alongside afforestation, biochar and direct air capture.
Why it matters
Durable, scalable removals are required for net zero; enhanced weathering is one of the few CDR methods with very long storage timescales (100,000+ years for ocean bicarbonate).