Carbon dioxide removal is a process in which it is removed from the atmosphere and stored in a carbon pool for long periods of time.
Carbon naturally travels between the atmosphere, ocean, plants, and rocks over time through a system called carbon cycle. We are altering this cycle by burning fossil fuels, which sends more carbon into the atmosphere in the form of greenhouse gases like carbon dioxide (CO2) and methane (CH4).
Extra greenhouse gases in the atmosphere cause earth warming. We are emitting so much of greenhouse gases that the amount of carbon dioxide in the air keeps increasing. Researchers are exploring ways to pull carbon dioxide out of the air in order to stop climate change.
Carbon dioxide removal (CDR) is a process in which CO2 is removed from the atmosphere and stored in a carbon pool for long periods of time. In the context of net zero greenhouse gas emissions targets, CDR is increasingly integrated into climate policy, as a new element of mitigation strategies.
Carbon dioxide removal is increasingly integrated into climate policy
CDR methods include afforestation, agricultural practices that appropriate carbon in soils, bio-energy with carbon capture and storage, ocean fertilization, enhanced weathering, and direct air capture (DAC) combined with storage.
Using giant fans, DAC facilities suck carbon dioxide out of the atmosphere and either store it underground in geological formations, or reuse it. Companies such as Carbon Engineering in Canada and Climeworks in Switzerland are developing this type of technology.
Climeworks has built the world’s largest DAC plant in Iceland, which began operations in 2021. The facility, known as Orca, is capable of capturing 4,000 metric tons of carbon annually, and pumping it underground where, when mixed with water, the gas will cool and turn into rock.
For clients like Microsoft, Stripe and Shopify, Climeworks provides carbon removal services and the company is successfully storing CO2 underground in a process that has been certified by DNV, an independent auditor.
Work on second commercial-sized plant now on
DNV has become the first firm to develop a methodology for checking how much CO2 has been pulled out of the atmosphere, transported, and permanently stored. The cost of CDR and storage depend on what quantity of carbon dioxide have to be removed and over what period of time, but the general price may go up to several hundred dollars per ton.
Climeworks has raised more than $780 million to scale up from a wide variety of investors including venture capitalist John Doerr and insurance company Swiss Re. The company has begun construction of its second commercial-sized plant in Iceland, which has a capacity to capture and store 36,000 metric tons per year of carbon dioxide.