CDR refers to techniques that remove CO₂ from the atmosphere and store it. In order for this collected CO₂ to be effectively removed from the cycle, permanent storage facilities, also known as carbon sinks, must be found. So far, neither economically profitable nor ecologically sustainable technologies have been found, although this would be indispensable for meeting the 1.5° target.
CO₂ sequestration (CCS) also refers to the permanent storage of CO₂, but with these technologies it is not filtered from the atmosphere but directly from the exhaust gases of power plants or industrial processes and stored on site. However,hese technologies are also viewed critically with regard to sustainability and profitability.
Nevertheless, research on these technologies will continue, because the later the target of net zero emissions is reached, the higher will be the need for negative emissions.
Sources: IPCC 2018 Special Report 15; Mark Jacobsen (Energy and Environmental Science 2, 2009)