Captain Drawdown’s daily logbook on every CDR story, paper, and expert voice — so you don’t have to read them all.
Mat Meredith went on the Raw Green podcast this week and framed his whole industry’s problem in five words. His team’s promo put it plainly: he sat down “for a wide-ranging conversation on enhanced rock weathering (ERW) and what it actually takes to prove carbon removal works” (@undocarbon on LinkedIn). Not what it takes to deploy. Not what it takes to fund. What it takes to prove. That word choice is the whole strategy, and the strategy has a postal code: Kingston, Ontario.
Meredith is Chief Product Officer at UNDO, the UK-founded company that spreads crushed silicate rock on farmland so it reacts with rainwater and locks away CO2, a pathway called enhanced rock weathering (we cover the basics in our weathering primer). Two years ago UNDO ran a pilot near Kingston. Today, on Meredith’s watch, Canada has become the company’s largest deployment footprint. The team said it out loud on Canada Day: “Two years ago, we began working in Kingston, Ontario. Today, Canada is home to our main operational base” (@undocarbon on LinkedIn). That is the fastest geographic pivot any major ERW company has made, and it was not an accident of logistics. It was a bet.
The work right now is a field season, not a fundraise. “Halfway through the year, and the 2026 field season is in full swing across Eastern Ontario,” the June impact update reads (@undocarbon on LinkedIn). Meredith thinks in agronomic time. Spreading windows, soil sampling rounds, harvest schedules. The Ontario program pairs rock application with dense soil instrumentation, because his argument on the podcast is that measurement, reporting, and verification, the MRV that turns a field into a credit, is the real gating constraint on ERW. Not basalt supply. Not trucking. Credibility.
So why here? Eastern Ontario looks like a strange place to prove a chemistry that runs on heat and rain. Cold winters slow weathering. But that is the point. The region offers glacial soils, humid summers, established row-crop agriculture, and farmers who already work with agronomists and keep records. It is a stress-test geography. If you can measure weathering signal through Ontario winters and glacial till, your methods will hold up almost anywhere. Add practical local factors: a stable regulatory environment, road access to quarries and cropland, and a farm sector used to soil amendment programs. Meredith is not choosing the easiest place to weather rock. He is choosing the hardest place to hide from an auditor.
The contrast that sharpens his lens arrived from Brazil. Mombak just generated the first Isometric-verified enhanced weathering credits from tropical soils, where heat and rainfall drive fast kinetics and credits arrive in months. Meredith’s bet is the opposite trade: slower weathering, denser instrumentation, a cleaner audit trail. And a new preprint gives his approach fresh urgency. Jessen et al. show that subsoil acidity can delay inorganic carbon sequestration in ERW by years, meaning the CO2 you think you captured in the topsoil can get released again deeper down before it reaches groundwater. That objection can only be answered with deep, sustained soil monitoring. Which is exactly what Ontario’s field program is built to produce.
Where is he heading? The bet is that by 2027, buyers underwriting ERW tonnes will pay a premium for defensibility over speed. The Brazil-versus-Ontario contrast is the choice that will shape this pathway’s price curve through 2030: fast tropical kinetics with newer monitoring stacks, or slower temperate weathering with clearer subsoil chemistry. Meredith is one of the few operators willing to defend the second answer in public, and to stake his company’s center of gravity on it.
Why his voice matters: ERW needs practitioners who treat skeptical papers as field-design specs rather than PR problems. The pathway will not scale on marketing. It will scale, if it scales, on boring, repeated, well-instrumented seasons in places like Eastern Ontario, feeding a portfolio of removal approaches that goes well beyond trees. And to be clear about the ceiling: none of this is a substitute for cutting emissions. ERW tonnes, like all CDR, are for residual emissions that cannot be abated, not a permission slip to keep burning.
What to watch: whether UNDO’s 2026 Ontario season produces the first temperate ERW credits verified against a major registry, and whether Meredith addresses the Jessen et al. subsoil-acidity finding head-on with field data rather than sidestepping it. If he does, Kingston stops being UNDO’s base and becomes the reference dataset for the whole temperate ERW market. Read his field reports before you read his marketing. My guess is he would tell you the same thing.
Citations
- LinkedIn — @undocarbon on LinkedIn — LinkedIn post
- LinkedIn — @undocarbon on LinkedIn — LinkedIn post
- LinkedIn — @undocarbon on LinkedIn — LinkedIn post
- arXiv preprint — subsoil acidity can delay inorganic carbon sequestration in ERW by years — preprint