Carbon Sequestration – Key to Climate Change Mitigation

Climate change remains a critical global challenge in 2025. Rising carbon dioxide (CO2) levels from human activities have accelerated global warming. Carbon sequestration has gained importance as a method to reduce atmospheric CO2 and stabilise the climate. This approach involves capturing and storing carbon in natural or engineered systems to slow temperature rise and protect ecosystems.

About Carbon Sequestration

Carbon sequestration is the process of capturing atmospheric CO2 and storing it to prevent its release. It occurs naturally through forests, soils, oceans, and wetlands. Technological methods include Carbon Capture and Storage (CCS) and Direct Air Capture (DAC). Both natural and artificial systems aim to restore the carbon balance disrupted by industrial emissions.

Natural Carbon Sinks

Forests absorb CO2 via photosynthesis and store it in biomass and soil. Afforestation and reforestation expand this capacity. Soils also hold large amounts of organic carbon, enhanced by sustainable farming practices like crop rotation, reduced tillage, and organic manure use. Wetlands, peatlands, and mangroves trap carbon under low oxygen conditions, limiting its release. Oceans absorb about 25% of global CO2 emissions, with marine plants and sediments playing a key role.

Technological Carbon Capture

CCS captures CO2 from industrial emissions and stores it underground in depleted oil and gas fields. DAC removes CO2 directly from the atmosphere using chemical processes. Emerging methods include mineralisation, where CO2 forms stable carbonates in rocks, and Bioenergy with Carbon Capture and Storage (BECCS), which combines biomass energy with carbon removal. These technologies are promising but currently expensive and require further development.

Global Potential and Benefits

Biological sequestration could offset up to 30% of annual CO2 emissions if scaled globally. Forests alone absorb around 2.6 billion tonnes yearly. Improved soil management offers additional storage. Geological reservoirs can hold vast CO2 quantities long-term. Benefits extend beyond climate mitigation, enhancing biodiversity, soil fertility, water retention, and food security. Carbon sequestration also supports green jobs and sustainable economies.

Challenges and Risks

High costs limit the adoption of CCS and DAC. Large-scale afforestation may compete with land for food production. Permanence of stored carbon is uncertain as forests may burn and soils degrade. Leakage from geological storage is a concern. Verifying carbon storage accurately remains difficult. Some experimental methods, like ocean fertilisation, carry ecological risks. Ethical and social issues must be addressed in implementation.

Policy and Global Initiatives

International frameworks like the Paris Agreement prioritise carbon sinks in emission reduction strategies. REDD+ incentivises forest conservation and sustainable management. Carbon markets reward verified sequestration projects. National programmes, such as India’s National Afforestation Programme and the US CarbonSAFE initiative, promote large-scale sequestration and innovation. Policies focus on integrating sequestration with renewable energy and sustainable agriculture.

Future Outlook

Advances in biotechnology may improve natural sequestration through genetically enhanced trees and crops. Technological breakthroughs in CCS, DAC, and carbon utilisation are expected to reduce costs and increase efficiency. Integration of carbon sequestration with circular economies and community participation is vital. Sustainable policy frameworks and incentives will ensure equitable and effective climate action.

Questions for UPSC:

1. Taking example of afforestation and reforestation, discuss their role in climate change mitigation and the challenges involved.
2. Examine the significance of Carbon Capture and Storage (CCS) and Direct Air Capture (DAC) technologies in achieving net-zero emissions by 2050.
3. With suitable examples, discuss how soil management practices can contribute to carbon sequestration and enhance agricultural sustainability.
4. Critically discuss the ethical and ecological concerns related to experimental carbon sequestration methods such as ocean fertilisation and mineralisation.

Answer Hints:

1. Taking example of afforestation and reforestation, discuss their role in climate change mitigation and the challenges involved.

1. Afforestation and reforestation increase forest cover, enhancing CO2 absorption via photosynthesis and biomass storage.
2. Forests act as major carbon sinks, currently absorbing about 2.6 billion tonnes of CO2 annually worldwide.
3. They help restore degraded ecosystems, improve biodiversity, and support water cycles.
4. Challenges include land competition with agriculture and human settlements, risking food security.
5. Forests are vulnerable to fires, pests, and climate stress, threatening carbon permanence.
6. Social issues arise from displacement, indigenous rights, and equitable benefit-sharing.

2. Examine the significance of Carbon Capture and Storage (CCS) and Direct Air Capture (DAC) technologies in achieving net-zero emissions by 2050.

1. CCS captures CO2 emissions directly from industrial sources, preventing atmospheric release.
2. DAC removes CO2 directly from ambient air, enabling negative emissions and offsetting hard-to-abate sectors.
3. Both technologies support continued industrial activity while reducing carbon footprint.
4. Current limitations include high costs, energy intensity, and technological maturity.
5. Large-scale geological storage offers long-term carbon sequestration potential.
6. Integration with renewable energy and bioenergy (BECCS) can enhance their effectiveness.

3. With suitable examples, discuss how soil management practices can contribute to carbon sequestration and enhance agricultural sustainability.

1. Practices like reduced tillage, cover cropping, and crop rotation increase soil organic carbon content.
2. Use of organic manure and compost improves soil fertility and carbon retention.
3. Healthy soils enhance water retention, reduce erosion, and increase resilience to climate extremes.
4. Soil carbon sequestration can offset several billion tonnes of CO2 annually if widely adopted.
5. Improved soil health leads to higher crop yields and food security.
6. Examples include conservation agriculture in India and regenerative farming in the US.

4. Critically discuss the ethical and ecological concerns related to experimental carbon sequestration methods such as ocean fertilisation and mineralisation.

1. Ocean fertilisation may disrupt marine ecosystems, cause harmful algal blooms, and affect biodiversity.
2. Potential unintended side effects include oxygen depletion and alteration of food webs.
3. Mineralisation is more stable but may require large-scale mining and energy input, raising environmental concerns.
4. Ethical issues involve governance, consent of affected communities, and long-term ecological risks.
5. Lack of comprehensive scientific understanding and monitoring complicates risk assessment.
6. Precautionary principle suggests cautious, regulated deployment until impacts are fully known.