BY RAMAN SENGHERA | APRIL 07, 2025 | Sustainability : The Fight Against GHGs
In the race against climate change, cutting emissions is only part of the story. We must also clean up the excess carbon dioxide (CO₂) already in our atmosphere to restore balance. That’s where Direct Air Capture (DAC) comes in—a cutting-edge technology that could help us reverse the clock on decades of carbon emissions.
DAC goes further than traditional offset schemes that aim to prevent new emissions. It actively pulls CO₂ out of the air, giving us a powerful tool to tackle past pollution while supporting the journey to a net-zero future.
But what exactly is DAC? How does it work? And can it be scaled up in time to make a difference? Let’s explore this fascinating climate innovation.
What Is Direct Air Capture?
Think of DAC as a giant air purifier for the planet. It uses specially designed systems to capture CO₂ directly from the surrounding air—no need to be near a factory or power plant.
Once captured, the CO₂ can either be:
- Stored safely underground, often in deep geological formations or
- It is used in synthetic fuels, fizzy drinks, fertilisers, or eco-friendly building materials.
This makes DAC a flexible solution—it can be set up almost anywhere with access to clean energy and proper storage or reuse infrastructure.
How Does It Work?
DAC systems generally fall into one of two categories:
- Liquid Solvent Systems
These pass air through a chemical solution that binds with CO₂. The CO₂-rich liquid is then heated to release pure CO₂, which can be captured. The solution is recycled back into the process.
Example: Carbon Engineering in Canada uses a potassium hydroxide (KOH) solution for this process.
- Solid Sorbent Systems
These use sponge-like materials that capture CO₂ on their surface. When the material is complete, it’s heated or depressurised to release the CO₂ and reused.
Example: Climeworks in Switzerland uses amine-coated filters in modular DAC units.
Both systems need energy—especially for heating and moving air. To deliver real climate benefits, that energy must come from renewable sources.
Why Is DAC So Important?
Here’s why DAC is more than just a shiny new tech:
- It Helps Undo the Past
Even if the world stopped emitting today, over 1.5 trillion tonnes of CO₂ would remain in our atmosphere. DAC is one of the few tools we have to remove that legacy pollution.
- It Supports Net-Zero Ambitions
Hard-to-decarbonise industries like aviation, agriculture, and cement will always have some emissions. DAC can help balance those out—something almost every net-zero plan relies on.
- It’s Geographically Flexible
Unlike traditional carbon capture, DAC doesn’t need to be near pollution sources. It can be located wherever conditions are ideal, offering far more freedom in design and deployment.
Who’s Leading the Charge?
Several pioneering companies and governments are pushing DAC forward:
- Climeworks (Switzerland): Running the world’s first commercial DAC + storage site, Orca, in Iceland. Their larger facility, Mammoth, is launching soon.
- Carbon Engineering (Canada): Partnered with 1PointFive and Occidental to build major DAC plants in the U.S.
- Global Thermostat (USA): Developing modular, solid-sorbent DAC systems.
Governments are stepping in, too. The U.S. Department of Energy is investing billions into regional DAC hubs, and the UK and EU are weaving carbon removal into broader climate strategies.
DAC and the Carbon Credit Market
DAC is growing in carbon markets—particularly at the premium end. Why?
- It physically removes CO₂ from the air, offering measurable, long-lasting climate benefits.
- Its credits are highly sought-after by companies looking for credible, verifiable net-zero solutions.
- Due to their reliability and permanence, DAC offsets often command higher prices than nature-based solutions.
Big names like Microsoft, Shopify, and Stripe already buy DAC credits, signalling strong corporate demand for this tech-forward solution.
The Challenges Ahead
Of course, DAC isn’t without its challenges:
- Energy Intensity
DAC systems need a lot of energy—especially for heating. Using renewables is essential, but that raises both the cost and complexity of deployment.
- High Cost per Tonne
DAC can cost anywhere from £400 to £800 per tonne of CO₂. That’s far more than reforestation, which can be under £20 per tonne. However, costs are expected to fall as technology improves and projects scale.
- Storage and Infrastructure
Captured CO₂ needs to go somewhere safe. That means building pipelines, storage sites, and monitoring systems—no small feat, especially across different countries and regulations.
- Public Trust
There’s concern that DAC might offer an excuse to delay real emissions cuts. We must see it as a supplement—not a substitute—for decarbonisation.
What Needs to Happen Next?
To realise DAC’s full potential, we’ll need:
- More considerable investments from both governments and the private sector.
- Supportive policies like carbon pricing, removal targets, and tax incentives (e.g., the U.S. 45Q credit).
- Reliable standards for monitoring, reporting, and verifying CO₂ removal.
- Stronger collaboration between companies, researchers, and governments to drive innovation.
It’s Part of the Solution, Not the Whole Answer
Let’s be clear: DAC is not a silver bullet. It won’t solve the climate crisis alone, but it is a valuable puzzle piece.
We still need rapid emissions cuts, massive renewable energy expansion, better land use, and protection of natural carbon sinks like forests and soils. DAC should complement these efforts—not distract from them.
Final Thoughts
Direct Air Capture is one of our climate tool’s boldest, most promising tools. It gives us hope that we can go beyond simply slowing climate change—and start to undo some of the damage.
DAC can grow from a niche technology into a global climate solution with the right mix of innovation, investment, and policy. One day, it might be as common as wind farms or solar panels—quietly pulling carbon from the sky and helping restore Earth’s delicate balance.
On the road to net zero, DAC reminds us that thinking big and acting fast are our best chances of making real progress.