Safe and permanent storage solutions that keep CO₂ out of the atmosphere are absolutely key. And to enable Carbon Dioxide Removal technologies to fulfill their foreseen role in climate change mitigation, these storage solutions have to be scalable to billions of tons of CO₂ per year.
Geological (underground) storage of CO₂ combines the scalability and technical maturity with safety and permanence. Furthermore, 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.
To conclude, geological storage in suitable rock formations in the deep underground is seen as the safest, most scalable and permanent approach of CO₂ storage as it is a natural process that is able to store CO₂. That is why Climeworks focuses on it.