Take on a podcast episode from Reversing Climate Change, originally published Thu, 18 Ju. Listen: https://podcasters.spotify.com/pod/show/reversingclimatechange/episodes/404-When-will-insetting-work-for-carbon-dioxide-removal-w-Tom-Mills--Stripe-Climate-Fellow-former-e3kugqp

TL;DR

  • Tom Mills (ex-Stripe Climate Fellow, now at Mati Carbon) argues insetting durable CDR into ag supply chains is harder than the industry assumes — useful reality check.
  • Coffee is the first ag value chain where biochar insetting actually pencils, driven by EUDR pressure, unmixed supply chains, and willing-to-pay CPGs. Plausible.
  • GHG Protocol forces removals onto a separate ledger from scope 3 reductions — a structural block on insetting demand that’s underdiscussed. Important.
  • “Supply shed” remains undefined; practitioners are setting norms by just doing it. Honest, slightly alarming.
  • Real insetting business model = stacking non-carbon benefits (yield, pesticide residue, nitrate leaching, biofortification), not selling the ton. Worth the hour for value-chain folks.

Ross Kenyon hosts Tom Mills — former Stripe Climate Fellow, now at enhanced rock weathering developer Mati Carbon (XPRIZE Carbon Removal grand prize winner) — on episode 404 of Reversing Climate Change. Mills spent his fellowship year on a single question: when does embedding biochar and enhanced rock weathering into Global South ag supply chains actually work? The honest answer is “not yet, and here’s why.”

What’s worth knowing. Mills’s central diagnostic is the GHG Protocol problem. Under current land-sector removal guidance, a durable removal generated inside a corporate’s own supply chain (say, biochar made from bagasse on a sugar estate) cannot be netted against scope 3 — it sits on a separate removals ledger. So the food-and-beverage buyers with the largest scope 3 footprints and the most natural geographic link to biochar/enhanced rock weathering activity have no clean accounting pathway to pay for the removal as a reduction. That’s a structural demand suppressor most CDR conversations skate past. Mills wants engagement on the next GHG Protocol iteration and, more tractably, on getting biochar and enhanced rock weathering into emission factor databases like Cool Farm Tool.

Why coffee leads, and the “prism” thesis. Coffee works as a first mover because the EU Deforestation Regulation pressures growers to keep production at lower altitudes (where soil amendments help), the bean isn’t blended across origins (clean farm-to-consumer line), and consumers absorb premiums. Mills cites a Colombian biochar coffee brand on-shelf. The broader insight: the unit economics of insetting only close when you stack non-carbon attributes — yield uplift, fertilizer-use efficiency, pesticide-residue reduction (rejected rice shipments at UK borders is his example), nitrate-leaching mitigation in poultry watersheds, biofortification of staple crops. Carbon alone won’t pay for it at scope-3-reduction prices, which he concedes are still “single digit integers.” Mills also flags a delivery-risk argument for distributed smallholder enhanced rock weathering over concentrated large-farm deployments — counterparty risk diversifies even as measurement, reporting, and verification (MRV) complexity rises.

Adjacent context. The supply-shed definition gap Mills describes is the same one that’s been dogging Isometric, Puro, and Cascade’s methodology debates for biochar — see prior CD coverage of Mati Carbon’s XPRIZE win and the Carbon Removal Industry Alliance Mills helped build. The non-carbon stacking thesis echoes what Alt Carbon is pitching in Darjeeling tea and what Lithos and Eion are quietly experimenting with on agronomic co-benefits. Wor