160 - How Direct Air Capture works

A look at a climate change solution

Author

The Climate Mentor
August 24th, 2025 • Estimated Reading Time: 4 minutes

Capturing CO₂ from thin air ♻️

Direct Air Capture (DAC) is a technology designed to remove carbon dioxide directly from the atmosphere - literally filtering the air we breathe.

Large fans draw ambient air into a system where it comes into contact with a chemical sorbent, often a liquid solution or a solid filter, that selectively binds CO₂ molecules while letting oxygen and nitrogen pass through.

Once saturated, the sorbent is regenerated through heat or pressure changes, releasing pure CO₂ that can then be handled as a concentrated stream. This process is essentially a form of industrial-scale air filtration, but at the molecular level.

What makes DAC especially compelling is its universality: unlike nature-based solutions such as reforestation, it doesn’t require vast tracts of land or depend on specific ecosystems.

In theory, DAC can be deployed anywhere, provided there is access to clean energy.

Illustration showing the carbon capture process. CO₂ from factories and vehicles is directed into a capture unit, where it is filtered. The cleaned air is released back into the atmosphere, while the captured CO₂ is injected underground for permanent storage. Trees and a person nearby represent the environmental benefits of cleaner air.

How Carbon Capture Works – From Emissions to Storage

From capture to storage and use🌱

What happens to the CO₂ after it is captured?

The key lies in ensuring it does not simply re-enter the atmosphere. There are two main pathways.

The first is permanent storage, where CO₂ is injected into deep geological formations. In places like Iceland, captured CO₂ is even mineralized into rock within a few years, locking it away for millennia.

The second is utilization, where CO₂ becomes a feedstock for products such as synthetic fuels, building materials, or even carbonated beverages. While utilization can reduce reliance on fossil sources, its climate benefit depends on how long the CO₂ remains out of the atmosphere.

The holy grail, therefore, remains permanent storage, which offers the clearest path to durable removal.

Aerial view of Climeworks’ Orca plant in Iceland, the world’s largest direct air capture facility. The site features modular CO₂ collectors attached to a central building, set in a green volcanic landscape powered by renewable geothermal energy. The captured CO₂ is permanently stored underground through mineralization.

Climeworks’ Orca Plant in Iceland – The World’s Largest Direct Air Capture Facility

Challenges and opportunites ahead

DAC has captured the imagination of policymakers, investors, and climate scientists because it directly addresses the “stock” of CO₂ already driving global warming.

However, it faces two key challenges: energy intensity and cost.

Today, removing one ton of CO₂ via DAC can cost between $500 and $1,000.

The hope is that, like solar photovoltaics, costs will decline dramatically as the technology scales. If supported by the right policies, investment, and innovation, DAC could become a cornerstone of the climate solution portfolio.

Crucially, it is not a substitute for reducing emissions, but a complement: we must both cut new emissions and remove unavoidable ones. DAC gives us the tools to do the latter, offering a way to clean up yesterday’s pollution while building a net-zero future.

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