Enhanced Rock Weathering

🌊 Vox Makes the Case for Marine CDR Vox published a major feature on ocean-based carbon removal, arguing it can address excess atmospheric CO₂ and ocean acidification simultaneously. Equatic plans to commission the world’s largest marine CDR plant in Singapore later this year, removing ~10 tCO₂/day via seawater electrolysis. The piece positions mCDR as a potentially superior pathway that doesn’t compete for agricultural land — but notes the field is “quite new” and MRV challenges remain. ...

🔬 Top Story: Cornell Study Puts ERW at Up to 1.1 Billion Tonnes/Year by 2100 A new study in Nature Communications Sustainability by Cornell’s Chuan Liao and colleagues models realistic adoption scenarios for enhanced rock weathering (ERW) — the practice of spreading crushed silicate rocks (like basalt) on agricultural fields to accelerate natural CO₂ drawdown. The findings: 350M–750M tCO₂/yr by 2050 and 700M–1.1B tCO₂/yr by 2100. That’s far below earlier theoretical ceilings of 5 Gt/yr but still a massive contribution to climate mitigation. A key takeaway: the Global South would eventually surpass the Global North in ERW deployment as supply chains mature, making the technique a potential equity lever for global carbon markets. (New Scientist · Nature) ...

A new study from Cornell’s Chuan Liao and colleagues, published in Nature Communications Sustainability, models what enhanced rock weathering (ERW) could actually achieve under realistic adoption scenarios. The headline: 700 million to 1.1 billion tonnes of CO₂ per year by 2100. That’s less than half the theoretical ceiling of 5 Gt/yr that earlier studies floated. But it’s still enormous — roughly 2–3% of current global emissions, achieved by spreading crushed basalt on existing farmland. ...

Five stories. Three continents. One theme: the CDR field is moving from theory to measurement. 🪨 ERW’s 1.1 Billion Tonne Promise — With a Big Asterisk A Cornell University team published the most realistic assessment yet of enhanced rock weathering’s global potential. Spreading crushed basalt on agricultural land could remove 350–750 Mt CO₂/year by 2050 and up to 1.1 Gt CO₂/year by 2100. The numbers are encouraging. Asia, Latin America, and sub-Saharan Africa have the highest potential — warmer, wetter climates accelerate mineral weathering, and farmers in these regions stand to benefit from the soil nutrient boost. ...

A new paper in Nature Reviews Earth & Environment has mapped out the uncertainties that still plague enhanced rock weathering (ERW) as a carbon dioxide removal strategy. Meanwhile, Germany’s Thünen Institute — a federal agricultural research body — has gone further, calling ERW “not yet a reliable climate protection measure.” This is getting attention, and it should. But let’s read past the headlines. What the Paper Actually Says The Nature paper doesn’t claim ERW doesn’t work. It catalogs the variables that make precise quantification difficult: soil type, mineral grain size, local climate, microbial activity, and leaching dynamics all influence how fast basalt dissolves and how much CO₂ is actually captured and stored. ...