Captain Drawdown’s daily logbook on every CDR story, paper, and expert voice — so you don’t have to read them all.

This week’s Bluesky chatter wasn’t about the next Microsoft-sized offtake. It was about something quieter and more consequential: Sara Vicca’s note that author teams for the IPCC 2027 Methodology Report on CDR Technologies, CCU and Storage are mobilizing. The fight over who defines durable removal has started, and the experts weighing in aren’t aligned.

“We are many to work on the IPCC 2027 Methodology Report on Carbon Dioxide Removal Technologies, Carbon Capture, Utilisation, and Storage (CDRT-CCUS). Great responsibility, many challenges ahead.”

  • Sara Vicca (@saravicca.bsky.social on Bluesky)

Vicca is understating it. This report will be the reference governments cite when writing compliance rules. The “many challenges” is code for boundary disputes: where does CCS end and CDR begin? Is CCU ever removal? Those calls get adjudicated here, not in voluntary market guidance.

“CDR-Startups stehen vor der unbequemsten Frage ihrer Existenz: Was verkaufen sie? Industrieller Rohstoff? Müllabfuhr? Philanthropie?”

  • Rico Grimm (@ricogrimm.de on Bluesky)

Grimm, writing in cleantech.ing, asks what CDR startups actually sell: industrial commodity, waste-management service, or philanthropy? Methodology bodies resolve this by fiat. Whichever answer the IPCC and EU encode will determine which of the three business models is even legal in compliance markets.

“Whether wetland restoration contributes to durable carbon removal is hard to know and remains the subject of much research, but it’s never a bad idea to restore wetlands for other ecosystem benefits.”

  • David Ho (@davidho.bsky.social on Bluesky)

Ho was reacting to Google’s wetland research funding near Mountain View. Note the structure of Google’s spend: research, not credits. Ho draws the bright line methodology writers often blur - co-benefits are not durable removal. If the IPCC team lets registries keep conflating them, the category’s integrity erodes before it’s built.

“‘Later is too late’ to get serious about renewables and valuing carbon… we talk about all the ways we can approach CO2 removal and the big opportunities for agricultural soils.”

  • Jennifer Pett-Ridge (@jeffinerca.bsky.social on Bluesky)

Pett-Ridge leads on Roads to Removal, the US CDR assessment. She’s pressing for soil carbon to sit inside the durable-removal tent. That’s a methodology fight the IPCC authors inherit directly, and it runs against Ho’s instinct to gate durability tightly. Both scientists are right about their own evidence. Only one framing can win in the rulebook.

“New study: most climate models underestimate the decline of the Atlantic overturning circulation. The AMOC is on course to slow by more than 50% by the end of the century.”

  • Stefan Rahmstorf (@rahmstorf.bsky.social on Bluesky)

Rahmstorf is the backdrop. Methodology debates happen against a climate system moving faster than models predicted. Getting definitions right the first time matters because there won’t be a calm decade to revise them.

The chorus reveals a shift. While trade press covers offtakes, the scientists shaping the rulebook are arguing about category boundaries, durability thresholds, and whether soil and wetlands count. The parallel fight inside the EU ETS overhaul and Wil Burns’s carbon takeback obligation proposal push the same question from different angles. Founders building pathways like enhanced weathering should be reading scoping documents, not just term sheets. The 2026-2027 methodology decisions will outrank any single buyer.