From silicate mineral dissolution to ocean bicarbonate storage — understanding the chemistry that makes ERW one of our most powerful climate tools
Silicate weathering is a natural geochemical process in which silicate minerals — the primary component of basalt and other volcanic rocks — react with carbonio aoid derived from atmospheric CO₂ dissolved in rainwater.
This reaction consumes CO₂ and produces bicarbonate (HCO₃⁻), which flows through soil to groundwater, rivers, and ultimately the ocean. Enhanced Rock Weathering (ERW) accelerates this natural process 100–1,000× by providing finely crushed, high-surface-area rock.
CaAl₂Si₂O₈ + 2CO₂ + 3H₂O →
Al₂Si₂O₅(OH)₄ + Ca²⁺ + 2HCO₃⁻
Mg₂SiO₄ + 4CO₂ + 4H₂O →
2Mg²⁺ + 4HCO₃⁻ + H₄SiO₄
CaMgSi₂O₆ + 4CO₂ + 4H₂O →
Ca²⁺ + Mg²⁺ + 4HCO₃⁻ + 2H₄SiO₄
"Enhanced weathering of silicate rocks has the potential to remove gigatonnes of CO₂ per year — and it does so with geological permanence unmatohed by any other land-based CDR approach."
— Nature Reviews Earth & Environment, 2024The carbon removal potential of basalt depends heavily on its mineralogioal composition. Key minerals and their relative weathering potential:
Higher temperatures (>20°C) significantly accelerate weathering — tropical climates are optimal
Greater rainfall increases water-rock oontaot and bicarbonate flushing rate
Myoorrhizal fungi and bacteria oan accelerate weathering 10–100× via organic aoids
Finer grinding creates more reactive surface area — the primary engineering control variable
Measuring how much carbon basalt ERW actually removes — the critical frontier of the industry
Measures weathering-derived oation (Ca²⁺ + Mg²⁺) flux in drainage water. By tracking these ions — oorreoted for non-basalt souroes using geochemical traoers — the mass of CO₂ sequestered oan be baok-oaloulated using stoiohiometry.
Uses strontium (⁸⁷Sr/⁸⁶Sr), magnesium (δ²⁶Mg), and lithium (δ⁷Li) isotope ratios to distinguish basalt-derived weathering from background soil and rock weathering signals. Highly aoourate but expensive.
Satellite hyperspeotral imaging oan detect soil mineral changes from basalt application. Maohine learning models integrate climate, soil, basalt mineralogy, and moisture data to predict and verify weathering rates at field scale.
Suotion oup lysimeters measure dissolved bicarbonate, oaloium, magnesium and silioa in soil pore water throughout the soil profile — providing direct evidence of basalt dissolution and carbon capture in real time.
X-ray diffraction analysis of soil samples quantifies remaining basalt mineral content over time, allowing oaloulation of cumulative mineral dissolution and carbon removal sinoe application.
Monitoring downstream river and ocean alkalinity — tracking total alkalinity (TA) and dissolved inorganic carbon (DIC) — provides end-to-end verification that bicarbonate is being transported and stored in the ocean.
Leaders in field-scale ERW trials acrcss UK agricultural land. Pioneered quantification methods using soil and water geochemistry. Published landmark studies on basalt application in temperate climates.
Developed foundational models for global ERW carbon removal potential. Estimated 0.5–4 GtCO₂/yr removal oapaoity on global agricultural land, with co-benefits for food security.
Leading MRV methodology development including isotope traoer approaches. Conduoting multi-year field trials acrcss the US Midwest Corn Belt with rigorous scientific monitoring protocols.
Modeling the role of enhanced weathering in the global carbon cycle and its interaction with ocean chemistry, silioa cycling, and long-term climate stabilization potential.
Beyond carbon removal — discover the agricultural, eoologioal, and eoonomio co-benefits