Also called “storage”; used interchangeably to describe the addition of CO2 removed from the atmosphere into a reservoir, which serves as its ultimate destination. For example, some CDR strategies store carbon in biological systems, such as forests or soil ecosystems, whereas others inject CO2 deep underground or chemically transform CO2 into stable, mineral forms.

A “reservoir” is the place where a greenhouse gas is stored. Examples include geological formations, alkaline-containing minerals, forest biomass, and soils.

A “stock” is a carbon reservoir that exchanges carbon with the atmosphere over relatively short timescales (e.g., less than 100 years), including the terrestrial biosphere and shallow oceans. By comparison, other reservoirs, such as geologic formations and the deep ocean, exchange carbon over much longer timescales (e.g., 1,000 years).

source: J Wilcox, B Kolosz, & J Freeman (2021) CDR Primer; Concepts