Negative emission technologies are undeveloped

The argument

Net-zero is an accounting identity with a technology hiding inside it. The 'net' concedes that substantial emissions will continue — from aviation, agriculture, cement, steel — and promises they will be cancelled by removing equivalent carbon from the atmosphere. Nearly every national net-zero plan and most of the pathways modelled by the Intergovernmental Panel on Climate Change therefore lean on negative emission technologies: direct air capture machines, bioenergy with carbon capture and storage, enhanced weathering, mass afforestation. The difficulty, critics point out, is that these technologies barely exist. Direct air capture currently removes a few thousand tonnes of carbon dioxide a year worldwide — a rounding error against the billions of tonnes the models assume it will swallow annually by mid-century. Bioenergy with carbon capture has never been demonstrated at meaningful scale, and the land it would demand competes directly with food production and ecosystems. Tree-planting schemes are routinely overcounted, vulnerable to fire and drought, and slow where the need is immediate. Scaling any of these by a millionfold in three decades would be an industrial mobilisation without precedent — assumed on spreadsheets, funded nowhere. The deeper objection is what the assumption does to behaviour today. Promised future removals license continued emissions now: every tonne a model expects machines to capture in 2050 is a tonne someone is excused from cutting in the present. Betting the climate on undeveloped technology is not a plan but a deferral, and it is why, on this argument, net-zero as currently constructed is not enough to prevent dangerous climate change.

Premises

Counter-arguments

The immaturity of removal technologies is an argument for building net-zero around deep, early emission cuts, not evidence that net-zero itself is insufficient to prevent climate change. Not all pathways lean heavily on removals; the most credible ones front-load rapid decarbonisation and reserve capture for a small residual of genuinely hard-to-abate emissions from aviation, cement and agriculture. The claim that promised removals 'license' continued emissions describes a risk of bad design and weak governance, not an inherent feature of the target. So undeveloped negative-emissions technology counts against over-reliance on it — and for a better-constructed net-zero — rather than showing the goal is inadequate.

Rejecting the premises

[Rejecting C] The objection targets excessive reliance on removals, which a well-designed net-zero pathway minimises, so it does not show that net-zero as such is not enough. [Rejecting P3] Whether future removals excuse present emissions depends on policy design, not on the net-zero target itself.