Enhanced Weathering: Spreading Rock Dust to Capture Carbon

Enhanced weathering is a removal technique that spreads finely crushed silicate rock over land or coast, where it reacts with carbon dioxide and water to form bicarbonates that store carbon and are eventually transported to the ocean. It sits inside Carbon Credits and connects directly to how projects are documented, financed, and judged.

Rock is quarried, crushed and spread on fields or beaches. As rainwater interacts with the minerals, carbon dioxide is consumed and bicarbonate is released, which moves into soils and waterways. Operators estimate uptake from rock mass, mineral composition, dissolution rates and field measurements of alkalinity and cation export. Because dissolution is slow, projects often combine modelling with measurements of alkalinity and cation export in drainage water, and the gap between the two is where most uncertainty sits.

The approach uses abundant materials and existing agricultural machinery, and it can improve soil pH and supply nutrients. Its potential scale is large enough to matter for national climate strategies. The technique also has agronomic appeal, since crushed silicate rock can raise soil pH and supply nutrients, giving farmers a reason to continue beyond the crediting period. Clarity about Enhanced weathering is what lets buyers, sellers, and regulators compare like with like instead of trading on assumption.

As carbon markets mature, Enhanced weathering is shifting from a niche technical concern to a mainstream one, shaping diligence checklists, disclosure expectations, and the way one credit or claim is weighed against another.

Dissolution rates are uncertain and vary with climate, grain size and soil conditions, so modelled uptake can overstate reality. Heavy metals in some rocks, dust from crushing, and downstream water chemistry effects are real environmental risks. Quantification is the weak point: a project can spread rock and claim modelled uptake, while field evidence of dissolution over a single season is often too noisy to confirm it.

CarbonFi requires rock provenance, geochemical composition and field monitoring for weathering credits, applying a conservative dissolution assumption so modelled uptake is not issued at face value. CarbonFi records grain size, application rate and site conditions for each weathering credit, because those variables drive dissolution and are the first thing an auditor will question. For teams working across CarbonFi, Enhanced weathering is not abstract: it maps onto concrete steps in verification, issuance, trading, or retirement, each of which can be recorded and checked on-chain.