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

The consensus is simple and everywhere: the world needs roughly 10 gigatonnes of durable carbon removal per year by 2050, and that number comes straight from the science of the Paris temperature targets. Buyers size their portfolios against it. Startups pitch against it. Policy-facing writing treats “closing the gap to 10 Gt” as the sector’s organizing problem, as in this Open Access Government piece on closing the carbon dioxide removal gap, which is a fair sample of how the framing gets deployed downstream.

The steel-man is real. Pathways that hold warming near 1.5°C do rely on large-scale removals in the second half of the century, and a sector this young needs a coordinating benchmark. A single, memorable number lets investors size markets, lets governments write procurement targets, and gives everyone a shared yardstick for measuring the gap between what exists and what is needed. Ambiguity is expensive. A crisp target, even an imperfect one, arguably beats a range nobody can rally around.

Here is the break. Rebecca Neumann traced the 10 Gt figure across roughly 50 sources in five sectors and published the result on CDRXIV: How carbon dioxide removal lost its way: tracing the origin and transformation of the 10-Gt durable CDR target. Her finding is not that the number appeared from nowhere. It is arguably worse than that. The figure traces back to IPCC scenario ensembles, but it sits above the ensemble median, and as it was re-cited across reports and decks it was transformed and stripped of the scenario assumptions that gave it meaning. It is not the direct output of any single integrated assessment model run keyed to 1.5°C. The industry has been treating a citation chain as a physical constraint.

Three more things the consensus glosses over. First, the demand number and the supply reality were never reconciled. A new Zenodo dataset, Disparities between Direct Air Carbon Capture and Storage Potential and Climate Target Demands by Fan and Zhang, is aimed at exactly that mismatch between what climate-target framings ask of direct air capture with storage and what deployment analysis supports. The dataset itself is restricted, so I will not put numbers in its mouth, but the research question alone tells you the reconciliation has not been done. Second, Hughes et al. on CDRXIV propose a warming-neutralization accounting framework in which an organization compensates for its emissions through a portfolio of mitigation strategies. That is a live alternative: you can define what “enough” means through warming outcomes and portfolio accounting, without anchoring on one headline tonnage. Third, the conditionality Neumann shows was stripped away matters enormously, because I have written before about how hard the buildout math already is at DAC’s current scaling trajectory. A target divorced from its scenario assumptions cannot tell you whether you are behind schedule or chasing a mirage.

The honest caveat: the consensus is right about direction. Essentially every pathway consistent with Paris requires gigatonne-scale durable removal for hard-to-abate residual emissions. Neumann’s paper does not argue for less CDR, and nothing here is a license to slow fossil-fuel phase-out. The dispute is about the denominator’s precision, not the sector’s necessity.

If Neumann’s read is correct, the implication is uncomfortable but useful. Strategies calibrated to “the gap to 10 Gt” are calibrated to a soft number, and they should be stress-tested against a target that moves by a factor of two in either direction. The tell to watch: whether major buyers and the IPCC’s next assessment cycle restate durable-CDR targets with uncertainty ranges and explicit scenario conditions attached, or keep quoting 10 Gt bare. If the number survives its own provenance audit, good. If it only survives because nobody re-reads the footnotes, that is a sector building on sand.

Citations

  1. DOI-resolved paper — Open Access Government piece on closing the carbon dioxide removal gap
  2. Cdrxiv — How carbon dioxide removal lost its way: tracing the origin and transformation of the 10-Gt durable CDR target
  3. DOI-resolved paper — Disparities between Direct Air Carbon Capture and Storage Potential and Climate Target Demands
  4. Cdrxiv — Hughes et al. on CDRXIV