The limitations of CCS and CDR and their grip on future climate
- The recently concluded COP28 brought attention to carbon capture and storage (CCS) and carbon-dioxide removal (CDR) technologies in addressing carbon emissions.
CCS and CDR Technologies
- Carbon Capture and Storage
- Involves capturing carbon dioxide (CO₂) at emission sources to prevent its release into the atmosphere.
- These sources include the fossil fuel industry and industrial processes like steel and cement production.
- Carbon Dioxide Removal
- Encompasses natural methods like afforestation and technological approaches such as direct air capture to absorb and store CO₂, mitigating its impact on climate change.
Scale and Challenges
- The success scale of CCS and CDR raises questions, especially considering the ambitious targets set by the IPCC's Sixth Assessment Report (AR6).
- IPCC scenarios suggest sequestering 5 billion tonnes of CO₂ by 2040, an amount exceeding India's current annual emissions.
- CDR is crucial for achieving the 1.5°C warming limit, as direct mitigation without it seems nearly impossible.
CCS Effectiveness
- Effective CCS applications require a capture rate of 90-95%, permanent storage of captured emissions and minimal methane emissions leakage.
- In reality, natural CDR has been used to offset existing emissions, raising concerns about shifting the mitigation burden away from reducing fossil fuel use.
CDR Challenges
- Land-based CDR methods like afforestation and reforestation face equity issues, impacting land rights of indigenous communities, biodiversity and competing with agriculture.
- Technological CDR at scale raises concerns about land use in the Global South, potentially affecting renewable energy generation and food security.
- CCS is still a technology under development without demonstrated feasibility at large scale despite decades of development.
Pitfalls of CCS and CDR
- There are concerns that CCS and CDR, by creating "room" to emit CO₂, may inadvertently encourage greenhouse gas emissions.
- Higher use of CCS and CDR may lead to emissions scenarios with a higher contribution from gas, potentially conflicting with emission reduction goals.