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9,566 tonnes of CO2, verified and issued from a single enhanced rock weathering batch on tea estates in West Bengal.
That is the new high-water mark for enhanced rock weathering, the process of spreading crushed silicate rock on land so it reacts with CO2 and locks it into bicarbonate. Until last week, no ERW operator had cleared five figures in one issuance. The previous reference points were a few thousand tonnes per batch from UK and US developers like UNDO and Lithos, plus Mombak’s first Isometric-verified ERW credits out of Brazil, which Captain Drawdown covered when Mombak generated its first batch. Alt Carbon, founded by brothers Shrey and Sparsh Agarwal, just roughly tripled the category ceiling in one shot.
The issuance was delivered to Frontier Climate, the Stripe-led advance-purchase consortium, under a Puro.earth-based protocol and reported by Carbon Herald. Verification rests on field sampling across multiple tea estates, cation tracking, and modeled CO2 uptake from basalt application. It is not the multi-year, multi-pathway dataset that Dirk Paessler (@dpaessler.bsky.social) is publishing from the Carbon Drawdown Initiative on 16 June, which “spans multiple soil types and feedstocks, and several years of sampling… plant tissue chemistry, soil carbon pools, cation retention, secondary mineral formation, and organic carbon stability.” Paessler’s standard is the one Alt Carbon’s MRV (measurement, reporting and verification) will be judged against next year. But the credits issued today met Puro.earth’s bar, and Frontier Climate bought them.
What this implies for the sector is straightforward. India is now the geography where the largest durable carbon dioxide removal supply contracts are being written. Indian biochar developer Equilibrium just signed a 180,000-tonne offtake with Altitude the same week. Western direct air capture, by contrast, is still issuing in the hundreds of tonnes. For ERW background, see Captain Drawdown’s primer on enhanced weathering.
The human scale of 9,566 tonnes is worth pausing on. Captain Drawdown’s headcount work found 9,499 full-time staff across 569 pure-play CDR startups globally. The Agarwal brothers’ operation just issued roughly one verified tonne for every person employed in the entire pure-play sector.
What the number does not tell us: it does not prove the basalt is weathering as modeled. Puro.earth’s protocol uses upfront issuance with a permanence assumption, not the multi-decade soil resampling that Jim Mann of UNDO argues for when he says SAT-C “is the critical unlock that will make enhanced rock weathering more credible, auditable and financially viable over time” (Jim Mann via UNDO on LinkedIn). Mann is writing the MRV bar that Alt Carbon now has to clear retroactively. The competitive moat for European and North American ERW operators is no longer “we can issue at all.” It is MRV depth, geological fit, and offtake durability.
What to watch: whether Alt Carbon’s next batch clears 20,000 tonnes before any Western ERW operator catches 9,566, and whether Frontier Climate’s buyer pool starts treating Indian basalt on tea estates as the default geography for the pathway. If both happen by mid-2026, the centre of gravity in enhanced weathering supply has moved east permanently.
Citations
- Carbon Herald — Carbon Herald
- Bluesky — @dpaessler.bsky.social — Bluesky post
- Carbon Herald — 180,000-tonne offtake with Altitude
- LinkedIn — Jim Mann via UNDO on LinkedIn — LinkedIn post