Captain Drawdown’s daily logbook on every CDR story, paper, and expert voice — so you don’t have to read them all.
This week in London, Jim Mann stood on the Carbon Removal Investment Summit stage and told a room of investors that enhanced rock weathering’s economics do not resolve on a spreadsheet. They resolve in a specific watershed, on a specific farm, with a specific basalt source feeding specific soil chemistry downstream. According to UNDO’s own recap of the panel, Mann’s argument was blunt: generic tonne accounting hides where ERW (enhanced rock weathering) actually works and where it does not.
That is the Jim Mann pitch in 2026. Geography first. Tonnes second.
The arc
Mann founded UNDO in the UK and built the company around a temperate, data-rich farm network: dairy pasture, mixed cropland, careful baselining. The early instinct was that the UK’s regulators, soil scientists, and field-trial culture would let UNDO answer the hardest question in ERW before anyone else could. That question is durability. How much CO2 actually stays removed, and for how long, when you spread crushed basalt on a real farm in a real climate.
The bet has gotten harder this year. Tropical competitors are moving faster.
The work
UNDO’s deployments are field-by-field, not regional. That choice is downstream of a science problem the Carbon Drawdown Initiative has been flagging publicly: cation fate is hyperlocal. Two adjacent fields can give very different durability answers depending on soil pH, drainage, and crop uptake. Mann has built UNDO around that reality rather than around it.
The per-hectare math here is dominated by rainfall, soil pH, and crop type, which is exactly the picture our Pathway 101 on Enhanced Weathering laid out earlier this year. Mann’s pipeline in the UK and Canada is essentially a wager that getting those variables measured properly, on temperate farms, produces credits a regulator will still respect in 2030.
The lens
Mann’s framing for CDR is that location decides everything. Same rock, different watershed, different answer. Same farm, different crop rotation, different cation pathway. He is one of the few founders making this argument loudly to capital allocators rather than burying it in a methodology appendix.
Chris Bataille (@chrisbataille.bsky.social) put the bigger thesis plainly: “That’s likely what CDR will mostly be; crushing the right rocks and dumping them in the ocean to carbonate.” A working climate economist endorsing rock-based removal as the dominant near-term pathway is the macro tailwind Mann is selling against.
Zeke Hausfather (@hausfath.bsky.social) agreed on direction but flagged the catch: “I’m broadly with you that rocks rather than energy is a more scalable approach to CDR, particularly near-to-medium term as we decarbonize everything else.” His worry is that actually measuring ERW is hard. That measurement, reporting, verification problem (MRV) is exactly the gap UNDO’s UK field network was built to close.
The tension
Here is where Mann’s geographic bet gets pressure-tested. InPlanet has been presenting at EGU 2026 on silicate rock powders in tropical Brazil, where weathering runs orders of magnitude faster than on UK dairy pasture. And as we covered when Mombak generated the first Isometric-verified ERW credits, Brazilian ERW credits hit the registry before UK ones did. That is the geographic plot twist of Mann’s year. Location, not lab pedigree, decided who issued first.
So the choice for buyers in 2026 is unusually clean. UK basalt on dairy pasture: slower kinetics, tighter MRV, durability you can defend in front of a regulator. Brazilian silicates on soy: faster reactions, messier baselines, credits issued sooner. Mann is betting the first profile survives the next round of integrity scrutiny. The tropical developers are betting the second profile gets to scale first and sets the standard.
Where he is heading
Captain Drawdown (@captaindrawdown.bsky.social) noted this week that OAE and ERW together hold roughly 100 Gt/yr of theoretical potential per IPCC AR6, with MRV as the catch. That size-of-prize is what turns Mann’s place-based MRV strategy from a research project into a multibillion-dollar wager.
What to watch: whether UNDO’s next verified issuance lands before or after the next tropical developer’s. The order of arrival on the Isometric and Puro registries will tell us which geography the standards bodies actually trust.
Why Mann’s voice matters
ERW is the pathway most likely to be sold on averages and bought on faith. Mann is the founder loudest about refusing both. If the durability story for rock-based CDR holds up by 2030, it will be because someone insisted, early, that the watershed mattered more than the spreadsheet. This week in London, that someone was him.
Citations
- LinkedIn — UNDO’s own recap of the panel — LinkedIn post
- LinkedIn — Carbon Drawdown Initiative has been flagging publicly — LinkedIn post
- Bluesky — @chrisbataille.bsky.social — Bluesky post
- Bluesky — @hausfath.bsky.social — Bluesky post
- LinkedIn — InPlanet has been presenting at EGU 2026 — LinkedIn post
- Bluesky — @captaindrawdown.bsky.social — Bluesky post