Carbon Removal: The Reality Behind the $1 Trillion Promise

The net-zero commitments of major economies rest on an assumption that tens of billions of tonnes of carbon dioxide will be removed from the atmosphere by mid-century. The current global capacity for engineered carbon removal — direct air capture, enhanced weathering, ocean alkalinity enhancement — is measured in thousands of tonnes per year, not billions. The gap between stated commitments and operational capacity is roughly four orders of magnitude.

What Carbon Removal Actually Includes

The category spans a wide range of approaches with very different cost, permanence, and scalability profiles. Nature-based solutions — forests, wetlands, soil carbon — are cheap and can be deployed now, but permanence is uncertain (forests burn) and verification is difficult. Bioenergy with carbon capture and storage (BECCS) is theoretically high-capacity but requires enormous land areas and faces serious sustainability questions. Direct air capture (DAC) is expensive ($300-$1,000 per tonne currently), energy-intensive, and technically proven at small scale, but needs to get to $100/tonne or below to matter at planetary scale.

Stripe, Microsoft, and a coalition of corporate buyers have committed to purchasing permanent carbon removal at above-market prices to subsidise technology development — the "buyer-side subsidy" approach. This has funded the first commercial DAC deployments: Climeworks's Mammoth plant in Iceland, 1PointFive's Stratos facility in Texas. Both are operating at roughly 36,000 tonnes/year capacity combined. The 2050 IPCC scenarios require 6-10 billion tonnes/year.

Where the Progress Is Real

Cost curves for DAC are moving in the expected direction. Climeworks's Orca plant cost ~$1,000/tonne; Mammoth targets ~$400/tonne; next-generation designs are projected at $200/tonne within this decade. The learning curve is following a pattern similar to early solar — not identical, because the physics are different, but the direction is credible.

Ocean-based approaches — enhanced weathering by spreading crushed olivine rock, direct ocean alkalinity enhancement — have compelling theoretical capacity (the ocean is a massive carbon sink) and are attracting serious research funding. The verification problem is significant: measuring actual carbon uptake in a dynamic ocean environment is technically challenging, and the regulatory framework for ocean-based removal doesn't exist yet.

What Is Being Oversold

Nature-based carbon offsets sold in the voluntary market have repeatedly failed independent verification. A 2023 Guardian investigation found that 90% of Verra-certified rainforest carbon offsets did not represent genuine emissions reductions. The methodological problems with forest carbon accounting — baseline setting, additionality, permanence — are well-documented and not yet solved. Corporations buying rainforest offsets to claim carbon neutrality are making claims that the underlying measurement science does not support.

The 2050 carbon removal scenarios assume that a technology barely past proof-of-concept today will scale by a factor of 100,000x in 25 years. Solar achieved a similar scaling, but carbon removal has an additional challenge: unlike solar, which displaces an existing energy market, carbon removal is a pure cost with no revenue stream except policy mandates or voluntary corporate commitments. The scaling requires sustained political will across multiple political cycles — a requirement that historical precedent suggests is difficult to guarantee.