Carbon capture and storage (CCS)
- CCS refers to technologies that can capture carbon dioxide (CO₂) at a source of emissions before it is released into the atmosphere.
- These sources include the fossil fuel industry (where coal, oil and gas are combusted to generate power) and industrial processes like steel and cement production.
Carbon-dioxide removal (CDR) technologies
- CDR takes the forms of both natural means like afforestation or reforestation and technologies like direct air capture, where machines mimic trees by absorbing CO₂ from their surroundings and storing it underground.
- There are also more complex CDR technologies like enhanced rock weathering, where rocks are broken down chemically; the resulting rock particles can remove CO₂ from the atmosphere.
- Other technologies like bioenergy with carbon capture and storage (BECCS) capture and store CO₂ from burning biomass, like wood.
Unabated fossil fuels
- At COP28, the term “unabated fossil fuels” has come to mean the combustion of these fuels without using CCS technologies to capture their emissions.
- Draft decision texts point to a need to “phase out” such unabated fossil fuels.
- On the other hand, removal technologies have been referenced in the context of the need to scale zero and low-emission technologies and support forest restoration as a means to promote emission removals.
Concerns regarding CDR
- CDR methods like afforestation, reforestation, BECCS, and direct air capture are constrained by their need for land.
- Land also invokes equity concerns.
- Land in the Global South is often considered to be ‘viable’ and/or ‘cost-effective’ for planting trees and deploying other large-scale CDR methods. As a result, such CDR projects can adversely affect land rights of indigenous communities and biodiversity and compete with other forms of land-use, like agriculture that is crucial for ensuring food security.
Challenges of CCS and CDR
- By removing CO₂ from their environment, there are concerns that CCS and CDR create more ‘room’ to emit the greenhouse gas.
IPCC assess
- In future emissions scenarios that the IPCC has assessed, the world’s use of coal, oil, and gas in 2050 needs to decline by about 95%, 60%, and 45% respectively (all median values) from their use in 2019 to keep the planet from warming by less than 1.5 degrees C with no or limited overshoot.
- But without CCS, the expected reductions are 100%, 60%, and 70% for coal, oil, and gas by 2050.