Carbon capture and storage (CCS) is the process of capturing waste CO2 and placing it into a geological storage site in such a way that it will not enter the atmosphere and contribute to further global warming. CCS uses several technologies, including absorption, chemical looping and membrane gas separation. Primarily aimed at large industry, carbon capture has actually been used for decades for various purposes. Its long-term storage, however, is a relatively new concept in the area of climate change mitigation.
In order for CCS to be effective, concentrated emissions are necessary. A carbon capture system placed on top of a factory, for example, works very well and is fairly cost efficient. As of 2019, 17 CCS projects were in operation globally, capturing 31.5 million tons of CO2 per year.
However, this method cannot easily be applied to CO2 present more generally in the atmosphere. Logistical difficulties notwithstanding, the costs of such an endeavor would be approximately USD 600 per ton. The wide-scale application of CCS necessary to make an impact on climate mitigation is some way away, with its true long-term efficacy still unknown. Investors subsequently view carbon capture as not currently having the scale to make a noticeable difference on global emissions, though the technology does have potential.