Ocean’s Role in Climate Change Mitigation

The ocean is crucial for moderating the Earth’s climate. It absorbs portion of carbon dioxide emissions and excess heat from greenhouse gases. This natural process gives humanity valuable time to address climate change. However, this capacity comes with consequences. Ocean acidification, pollution, and disrupted ecosystems threaten marine life and the services oceans provide, such as fisheries and carbon sequestration.

Ocean Acidification and Its Effects

Ocean acidification occurs when carbon dioxide dissolves in seawater, lowering pH levels. This process endangers calcifying organisms like corals and shellfish. Warming waters also disrupt circulation patterns and deplete oxygen levels in marine habitats, leading to widespread ecological consequences.

Marine Carbon Dioxide Removal (mCDR)

In response to climate challenges, marine carbon dioxide removal is gaining attention. mCDR strategies aim to complement emissions reductions. These methods focus on the ocean’s ability to absorb and store carbon. They are divided into biotic and abiotic approaches.

Biotic Approaches

Biotic methods utilise living systems for carbon capture. Mangroves, macroalgae, and river systems play a role in sequestering carbon. While these solutions support biodiversity, their carbon capture potential is limited. They can sequester less than one billion tonnes of carbon dioxide annually, with storage lasting only hundreds to thousands of years.

Abiotic Approaches

Abiotic techniques offer greater scalability and permanence. For instance, biomass burial at sea can sequester between seven to 22 billion tonnes of carbon dioxide each year. Ocean alkalinity enhancement (OAE) involves adding alkaline materials to seawater. This method can lock away carbon for tens of thousands of years, with a potential capture of one to 15 billion tonnes of carbon dioxide annually.

Challenges of mCDR

Despite its promise, mCDR faces important hurdles. Public scepticism exists regarding the safety and efficacy of abiotic techniques. Regulatory challenges and energy requirements for some methods also pose obstacles. Measuring the effectiveness of carbon capture in vast ocean spaces is another complex issue.

Importance of Governance and Trust

Successful implementation of mCDR relies on rigorous science, robust governance, and societal trust. Transparent communication and stakeholder engagement are essential to overcome public doubts. mCDR should not replace emissions reductions but serve as a complementary strategy in the transition to net-zero emissions.

Potential of the Indian Ocean

The Indian Ocean holds important potential for deep carbon burial. It could capture a substantial percentage of marine carbon dioxide. However, India has yet to fully explore its rivers and seas for climate solutions. Harnessing these natural systems could provide a critical advantage in combating climate change.

Questions for UPSC:

1. Critically analyse the impact of ocean acidification on marine ecosystems.
2. What are the biotic and abiotic approaches to marine carbon dioxide removal? Compare their effectiveness.
3. Estimate the potential of the Indian Ocean in mitigating climate change through carbon burial.
4. Point out the challenges faced by marine carbon dioxide removal techniques in public perception and regulatory frameworks.

Answer Hints:

1. Critically analyse the impact of ocean acidification on marine ecosystems.

1. Ocean acidification results from increased carbon dioxide dissolving in seawater, lowering pH levels.
2. This process threatens calcifying organisms such as corals and shellfish, crucial for marine biodiversity.
3. Warming waters disrupt ocean circulation patterns, leading to oxygen depletion in vital habitats.
4. Altered ecosystems can affect fisheries, food webs, and the overall health of marine environments.
5. Long-term consequences may include loss of biodiversity and diminished ocean services like carbon sequestration.

2. What are the biotic and abiotic approaches to marine carbon dioxide removal? Compare their effectiveness.

1. Biotic approaches utilize living systems (e.g., mangroves, macroalgae) to sequester carbon, supporting biodiversity.
2. These methods have limited carbon capture potential (less than 1 billion tonnes annually) and shorter storage durations.
3. Abiotic approaches, like biomass burial and ocean alkalinity enhancement, offer greater scalability and permanence.
4. Abiotic techniques can sequester 7-22 billion tonnes (biomass burial) or 1-15 billion tonnes (OAE) of carbon dioxide annually.
5. While abiotic methods may capture more carbon, they face public skepticism and regulatory challenges.

3. Estimate the potential of the Indian Ocean in mitigating climate change through carbon burial.

1. The Indian Ocean could capture approximately 25-40% of marine carbon dioxide through deep carbon burial.
2. This potential is important given the ocean’s vastness and its ability to store carbon long-term.
3. India has not yet fully explored the transformative potential of its rivers and seas for carbon capture.
4. Utilizing these natural systems could enhance India’s climate change mitigation strategies.
5. Effective harnessing of the Indian Ocean’s potential requires investment in research and technology.

4. Point out the challenges faced by marine carbon dioxide removal techniques in public perception and regulatory frameworks.

1. Public skepticism exists regarding the safety and effectiveness of abiotic carbon removal techniques.
2. Many people prefer biotic approaches or terrestrial solutions, viewing abiotic methods as unnatural or harmful.
3. Regulatory challenges hinder the implementation of innovative mCDR strategies, requiring comprehensive frameworks.
4. Energy-intensive processes for some methods raise concerns about their overall sustainability and environmental impact.
5. Transparent communication and stakeholder engagement are essential to build trust and overcome doubts.