Captains-Log

Captain Drawdown’s daily logbook on every CDR story, paper, and expert voice — so you don’t have to read them all. Four European CDR modeling papers hit arXiv in a single week, and read together they expose an uncomfortable truth: the headline cost numbers for direct air capture and CO2 removal portfolios are governed less by chemistry or geology than by undisclosed assumptions about future carbon prices. Those assumptions diverge by an order of magnitude across teams, and almost none of the papers treat the divergence as the headline variable. ...

Captain Drawdown’s daily logbook on every CDR story, paper, and expert voice — so you don’t have to read them all. The pattern this week is sharp. Public balance sheets are moving into capture infrastructure faster than private capital is willing to underwrite it. BP wants out of UK clusters. Berlin and Brussels are writing the largest decarbonization cheques in European history. The counterparty stack for durable CDR is being rebuilt in real time. ...

Captain Drawdown’s daily logbook on every CDR story, paper, and expert voice — so you don’t have to read them all. Microsoft is reportedly negotiating away its 24/7 carbon-free electricity pledge while New York waters down its climate statute. The voluntary buyer model that built durable CDR’s offtake pipeline is showing strain in the same week. Here is what people watching the seams said. “Voluntary measures were never gonna get us where we need to be on emissions. But the fact that data center growth has made it corporate-ly/socially acceptable for a big tech company with ambitious climate goals to abandon them seems like a really bad sign.” ...

Captain Drawdown’s daily logbook on every CDR story, paper, and expert voice — so you don’t have to read them all. CarbonPlan published a finding on Tuesday that should reset how every buyer, registry, and supplier in enhanced rock weathering thinks about their MRV stack. In How surface roughness scaling can mislead enhanced weathering predictions, the team shows that a mistaken surface area equation used in some widely circulated ERW (enhanced rock weathering) models can inflate predicted carbon removal by up to two orders of magnitude. That is a 100x overstatement. It lands in the same week Mombak issued the first Isometric-verified ERW credits, Boeing expanded its ERW offtake position, and Brazil moved the pathway into sovereign compliance market discussions. The timing is brutal, and that is exactly why it matters. ...

Captain Drawdown’s daily logbook on every CDR story, paper, and expert voice — so you don’t have to read them all. Three contracts crossed three different borders this past week, and together they tell a story the tonnage debate keeps missing. CDR’s binding constraint is no longer chemistry or capture cost. It is the legal pipework for moving and storing CO2 across boundaries that were never designed to be crossed. ...

Captain Drawdown’s daily logbook on every CDR story, paper, and expert voice — so you don’t have to read them all. Five numbers from the past week. Together they sketch a market where buyers are writing bigger checks than ever, while the people, electrons, and dollars-per-ton math underneath those checks remain stubbornly thin. The demand side is sprinting. The supply side is still putting on its shoes. 20,000 tonnes. Boeing’s new portfolio purchase through Supercritical, sourced from biochar and enhanced rock weathering, is among the largest aviation-linked durable CDR offtakes inked for 2026. The signal matters as much as the volume: ERW (enhanced rock weathering, where crushed silicate rock pulls CO2 out of the air as it weathers) is now considered procurement-grade alongside biochar. That is a credibility milestone we flagged when Mombak generated the first Isometric-verified ERW credits. ...

Captain Drawdown’s daily logbook on every CDR story, paper, and expert voice — so you don’t have to read them all. A Stanford-led paper in Nature Communications Sustainability dropped this week and broke the CDR feed open. Direct air capture has substantial health and climate opportunity costs argues that $100M/year on utility-scale wind or solar beats DAC on combined climate and health benefits across nearly every U.S. grid region through 2050. The fight isn’t over the numbers. It’s over whether the equation is the right one. ...

Captain Drawdown’s daily logbook on every CDR story, paper, and expert voice — so you don’t have to read them all. Three deals this week show the same pattern. Hyperscaler and industrial buyers are not buying carbon removal credits anymore. They are buying portfolio construction services from a thin layer of intermediaries who now sit between every supplier and every dollar. Start with Boeing. The aerospace giant just contracted for 20,000 tonnes of removal across biochar and enhanced rock weathering, a process that grinds silicate rock to speed up natural CO2 absorption. But Boeing did not pick the suppliers. Supercritical assembled a six-supplier basket across two pathways and sold it as a single product. The buyer outsourced the diligence. ...

Captain Drawdown’s daily logbook on every CDR story, paper, and expert voice — so you don’t have to read them all. The rock-based carbon removal pathway has quietly stopped being a science project and started being a mining-industry pivot. Three announcements in three weeks, on three continents, all point to the same insight: tailings piles are the new feedstock asset class for durable CDR. Start with Quebec. The Quebec Surficial Mineralization Hub launched with Frontier backing, and the framing is what matters. Frontier called Quebec’s industrial legacy, meaning its mining tailings, “one of the world’s biggest carbon removal opportunities.” Liability becomes feedstock. The throughput numbers are not small either. “Not spreading, either aerating large piles or using reactors. You do end up getting more mass at the end than you dig up due to carbonation, but we still expect on the order of >30k tons CO2 stored per acre.” - Zeke Hausfather (@hausfath.bsky.social on Bluesky). Per-acre density at that level is what separates a serious feedstock thesis from a boutique demo. ...

Captain Drawdown’s daily logbook on every CDR story, paper, and expert voice — so you don’t have to read them all. While CDR Twitter argued about Microsoft’s procurement pause and Verra methodology fights, climate scientists were having a louder week. The physical signal got worse, the political ceiling got higher, and the people who study this for a living are not whispering. Here is what they said. “The new ‘Indicators of Global Climate Change 2025’ preprint (Forster et al.) shows a tripling of Earth’s Energy Imbalance relative to 1976-1995, using a IPCC AR6 methodology!” ...