Carbon Removal, Explained: DAC, Enhanced Weathering, and Ocean Methods

Carbon removal has crossed an awkward threshold. It is no longer a lab curiosity, but it is not yet a climate solution at scale either. Real companies now sell removed CO2 at published prices, and governments write tax codes around it. The catch is the math: humanity emits about 42 gigatons of CO2 per year, IPCC scenarios call for 6 to 20 gigatons of yearly removal by mid-century, and novel removal methods currently pull down roughly 0.0013 gigatons a year, according to NOAA.

Direct air capture

Direct air capture, or DAC, does exactly what the name says: giant fans pull ambient air through a chemical filter that grabs CO2, which is then released in concentrated form and stored underground. Climeworks uses solid sorbent filters. Carbon Engineering, now part of Occidental's 1PointFive venture, uses a liquid solvent of potassium hydroxide. Heirloom takes a passive route, spreading limestone-derived material that absorbs CO2 without fans.

Cost is the whole story with DAC. Climeworks currently charges $600 to $1,000 per ton, with retail buyers paying around $900 per tonne, and targets $250 to $350 per ton by 2030. In May 2026 it announced a Generation 3 technology it says could halve removal costs, though that is still moving from lab to deployment. Carbon Engineering's liquid-solvent route is rumored near $400 per ton in contracts, and the weighted average for DAC with storage across disclosed deals is about $516 per ton, per CDR.fyi data from October 2026.

Scale is coming, slowly. Occidental's Stratos plant in Texas, a roughly $1.3 billion facility designed to pull 500,000 tons a year from the air, has faced delays. The demand side is healthier: Microsoft alone has contracted more than 45 million tons of removal, and the Frontier advance market commitment from Stripe, Alphabet, Meta, and Shopify totals around $1 billion. DAC's fundamental constraint is energy. Scrubbing a gas that makes up 0.04 percent of air takes enormous power, so plants only make climate sense on clean electricity with verified geological storage nearby.

Enhanced weathering

Enhanced weathering speeds up a geological process that already removes CO2. Certain rocks, especially basalt and olivine, react with CO2 and water to form bicarbonate, which washes through rivers into the ocean and stays locked up for millennia. Companies crush these rocks and spread them on farmland, where rain does the chemistry.

The appeal is ramp-up speed. Unlike DAC, there is no billion-dollar plant to build: rock, trucks, and fields. Prices sit well below DAC, with Eion selling credits in the $300 to $400 per ton range and its Frontier offtake landing just under $420 per ton. Lithos signed a $57.1 million agreement with Frontier buyers to remove 154,240 tons between 2024 and 2028, roughly $370 per ton. The disclosed-deal average across the sector is about $352 per ton, and companies are targeting under $200 to $300 as operations scale.

There are co-benefits farmers actually want: crushed basalt substitutes for conventional agricultural lime, and Lithos has reported yield improvements of up to 47 percent in some trials. The hard part is measurement. Proving how much CO2 a given field absorbed requires soil sampling and geochemical fingerprinting rather than simple models, and typically 40 to 70 percent of applied mineral dissolves within six to nine months. Researchers estimate the global potential at around 2 gigatons per year, which would be meaningful if the logistics and verification hold up.

Removing a ton of CO2 from the air costs anywhere from $135 to $1,000 today. The entire industry is a bet that engineering and scale push every method toward the cheap end.

Ocean methods

The ocean already holds about fifty times more carbon than the atmosphere, which makes it a tempting place to stash more. Ocean carbon removal splits into several approaches. Ocean alkalinity enhancement adds alkaline minerals to seawater so it absorbs more CO2 from the air. Direct ocean capture uses electrochemistry to pull dissolved CO2 straight out of seawater. Others cultivate seaweed or sink biomass into the deep ocean.

This is the youngest branch of the family. Equatic runs an electrochemical process developed at UCLA: a $20 million demonstration plant in Singapore is commissioning, and a planned Quebec facility would remove nearly 110,000 tons a year while producing hydrogen. In April 2026 the US EPA issued its first permit for a company, Carboniferous, to deposit biomass bricks on the deep ocean floor off Louisiana. Frontier awarded $2.1 million to four ocean alkalinity projects in 2026, and the US Department of Energy committed $36 million across eleven marine CDR projects.

The limits are bigger here than anywhere else. Measurement is brutally hard in open water, ecological side effects are poorly understood, and ocean dumping rules add permitting risk. Analysts value the whole ocean CDR market at under $900 million in 2026: a research portfolio with commercial ambitions, not a scaled industry.

Biochar, BECCS, and the limits that apply to everything

The workhorse of actual carbon removal in 2026 is not a futuristic machine. It is biochar: waste biomass heated without oxygen into a stable charcoal buried in soil, locking carbon away for centuries. Biochar represented 86 percent of worldwide CDR deliveries in 2024, and credits trade around $135 per ton on the Puro.earth index. Its weakness is fragmentation: a 2026 review of eight biochar crediting protocols found prices swinging from $90 to $600 per ton for the same activity, because accounting rules differ so much.

BECCS, bioenergy with carbon capture and storage, burns biomass for power and captures the exhaust, averaging about $220 per ton in disclosed deals. Switzerland saw its first commercial BECCS shipment in 2026. Both methods live or die on sustainable feedstock: diverting land or forests to grow fuel can erase the climate benefit.

Three honest limits apply to every method. First, permanence varies enormously, from decades for forest carbon to millennia for mineralized CO2, and prices mostly reflect that. Second, energy and land budgets are real: DAC needs vast clean power, weathering needs vast rock logistics, and BECCS needs vast biomass. Third, removal is not a substitute for cutting emissions. The gap between 42 gigatons emitted and a thousandth of a gigaton removed is the single most important number in this field. Policy helps the economics, through the US 45Q storage credit and Europe's first full-scale storage projects, but the industry's promise still rests on the bet solar once made: that costs fall with scale. The difference is that the atmosphere cannot wait as long as the grid did.

References

CDR.fyi disclosed deal prices via Regreener; NOAA novel CDR estimates via Value Market Research; Climeworks cost and Generation 3 reporting via Enkiai and Global Brands Magazine; ETH Zurich DAC cost study via ScienceDaily; Eion and Lithos offtake reporting via AgFunderNews and Global AgInvesting; Reuters on enhanced rock weathering; Equatic plant reporting via ENR; EPA Carboniferous permit via E&E News; Frontier and DOE marine CDR funding via Carbon Removal Updates; biochar market data via GlobeNewswire and Biochar Today; biochar protocol review, Mukhopadhyay et al., EarthArXiv 2026; IPCC removal scenarios via the Carbon Capture Wiki.