Carbon dioxide removal (CDR), also known as carbon removal, greenhouse gas removal (GGR) or negative emissions, is a process in which carbon dioxide gas () is removed from the atmosphere by deliberate human activities and durably stored in geological, terrestrial, or ocean reservoirs, or in products. In the context of net zero greenhouse gas emissions targets, CDR is increasingly integrated into climate policy, as an element of climate change mitigation strategies. Achieving net zero emissions will require both deep cuts in emissions and the use of CDR. CDR can counterbalance emissions that are technically difficult to eliminate, such as some agricultural and industrial emissions.
CDR methods include afforestation, reforestation, agricultural practices that sequester carbon in soils (carbon farming), wetland restoration and blue carbon approaches, bioenergy with carbon capture and storage (BECCS), ocean fertilization, ocean alkalinity enhancement, and direct air capture when combined with storage, To assess whether negative emissions are achieved by a particular process, comprehensive life cycle analysis of the process must be performed.
As of 2023, CDR is estimated to remove around 2 gigatons of per year, which is equivalent to 4% of the greenhouse gases emitted per year by human activities. There is potential to remove and sequester up to 10 gigatons of carbon dioxide per year by using those existing CDR methods which can be safely and economically deployed now.
Carbon dioxide removal (CDR) is defined by the IPCC as:
Anthropogenic activities removing from the atmosphere and durably storing it in geological, terrestrial, or ocean reservoirs, or in products. It includes existing and potential anthropogenic enhancement of biological or geochemical sinks and direct air capture and storage, but excludes natural uptake not directly caused by human activities.
Synonyms for CDR include greenhouse gas removal (GGR), negative emissions technology, and carbon removal.