Despite having major implications for climate change, CO₂ is actually a relatively small percentage of the overall makeup of the atmosphere — about 0.04% (Forster, P. M., C. Smith, T. Walsh, et al., 2024). DACCS systems are designed to selectively isolate and remove this small fraction from large volumes of air. This is achieved through specialized sorbent- or solvent-based systems (McQueen, N., K. V. Gomes, C. McCormick, et al., 2021).

In solid sorbent systems, large fans draw in ambient air across porous materials that chemically bind to CO₂ molecules. In liquid systems, air dissolves into amine-based solutions that react with CO₂. Once the material is saturated, the CO₂ is separated again through temperature  or pressure changes, and the capture medium is regenerated for reuse. The result is a purified, concentrated stream of CO₂, ready for transport and storage (McQueen, N., K. V. Gomes, C. McCormick, et al., 2021).

The core capture process is rooted in well-understood chemical engineering principles. The underlying technologies have benefited from decades of development in related industries such as industrial gas processing, air purification, and carbon capture for fossil-based systems. This gives DACCS a solid technical foundation for further optimization and scale.

DACCS achieves durable carbon removal when the captured CO₂ is stored in a way that prevents it from returning to the atmosphere. The most common storage method is geological sequestration, where CO₂ is injected into deep rock formations such as saline aquifers or depleted oil and gas reservoirs. Alternatively, it can be used in durable materials, such as concrete, locking the carbon into products with long lifespans.

Each of these pathways provides storage durations measured in centuries to millennia, ensuring long-term climate impact.

One of the defining features of DACCS is its ability to operate independently of biomass availability, land use, or soil conditions. This makes it uniquely adaptable for deployment near CO₂ storage sites or in locations with abundant renewable energy.

Most DAC systems are modular by design, allowing for incremental scaling. This opens opportunities for both centralized large-scale plants and distributed regional systems. According to the IEA, more than two dozen DAC facilities are already operational worldwide.

DACCS is projected to capture more than 85 million tonnes of CO₂ per year by 2030, and around 980 million tonnes annually by 2050 (IEA). These projections reflect the growing momentum behind DACCS as a climate solution, supported by increasing investment and policy support.

However, DACCS remains energy-intensive. Capturing CO₂ from the atmosphere requires power for fans, sorbent regeneration, and compression. Current systems require 5–10 gigajoules of energy per tonne of CO₂ (IEA), and scaling to gigatonne levels would demand approximately 50 exajoules annually by 2100 — roughly 10–15% of projected global energy production.

Compared to biochar, which is already widely deployed and used today, DACCS lags behind in terms of technological readiness and deployment, though it is rapidly advancing with increasing investment and policy support.

This makes the availability of low-carbon energy a key enabler for future growth. Continued innovation in material science, process efficiency, and integration with renewable energy systems will be critical to reducing both the energy footprint and cost of DACCS. These advances are already underway, with new generations of capture materials and system designs under development across the sector.