Why do we need to store CO₂?

Carbon dioxide (CO₂) is a greenhouse gas that traps heat and warms the planet and, for over a hundred years, it has been extracted from the Earth’s core, instigating climate change. CO₂ is not the only gases contributing to climate change. Still, it accounts for 81 percent of all greenhouse gas emissions and can linger in the atmosphere for thousands of years (i.e. methane has a lifetime of a decade). While it’s true that plants, trees, and algae transform CO₂ into oxygen through photosynthesis, the ocean absorbs and stores CO₂ in ocean sinks. It is also true that nature cannot bear the rising levels of human-made emissions and that is why, in addition to efforts that reduce emissions, we need to capture and remove CO₂ from the air.

What is underground mineralization of CO₂?

Underground mineralization of CO₂ is the process of injecting the captured CO₂ into the pores of rock formations deep underground, where it is physically trapped through mineralization and thus permanently stored.  It is a fully natural and safe solution as it is only accelerating a natural process, plus it is permanent, as it is stable for millennia.

It is essential to emphasize that mineralization is a process that has been occurring in nature for millions of years, being the main mechanism by which the planet regulates atmospheric carbon dioxide. However, the Earth's natural carbon mineralization occurs on a very slow timescale that cannot keep up with human-made emissions rates. That is why we partner with companies like Carbfix, which mirror the natural process and accelerate it. Our Icelandic CO₂ storage partner has shown that it can be done naturally and permanently in less than two years by storing CO₂ from 800 to 2,500 meters underground.

How Climeworks' storage works with Carbfix

How direct air capture and storage (DAC+S) works

How does underground mineralization of CO₂ work?

Once the captured CO₂ is collected using our direct air capture technology process, the CO₂ storage via underground mineralization can begin. This can be done in different parts of the world – we only need a source of renewable energy and the possibility to mineralize the CO₂ .


Our CO₂ storage partner, Carbfix in Iceland, can turn CO₂ into stone in less than two years. They dissolve the CO₂ in water – sparkling water of sorts – and inject it underground where it reacts with basalt rock to form solid carbonate minerals via natural processes.

CO₂ turned into stone with the Carbfix process

CO₂ turned into stone with the Carbfix process


With 44.01’s technology, we are exploring a new storage location: Oman. Their technology dissolves the captured CO₂ in water to create CO₂ charged water. This is then injected into peridotite rock formations underground.

CO₂ turned into stone with the 44.01 process

CO₂ turned into stone with the 44.01 process

Let’s go a bit deeper

Is it safe? The pioneering process of turning carbon dioxide into stone is safe as it reproduces a natural process. It happens through a combination of carbon dioxide capture from the air and rapid underground mineralization - a natural process whereby the carbon dioxide reacts with the basaltic rock to become solid calcite matter (another form of rock) within a few years.

How much CO₂ can be stored? The short answer is: All of it. Scientific estimates show that the global potential for geological storage of CO₂ outweighs all greenhouse gases ever emitted since the Industrial Revolution approximately by a factor of 3.

How long does it take? As our Icelandic CO₂ storage partner Carbfix demonstrated, over 95% of CO₂ captured and injected at Hellisheidi Geothermal Power Plant is mineralized within two years. The remaining 5% turns into stone shortly thereafter.

If you're interested in learning more, take a look at our blog and publications: