The ocean plays a significant role in climate moderation by carbon absorption and heat regulation.

Role of Ocean in Regulating Climate

• Heat Absorption and Distribution
  • Heat Sink: The ocean absorbs over 90% of the excess heat generated by greenhouse gases, acting as a massive heat sink. This helps to moderate global temperatures and prevent rapid climate change.
  • Heat Transport: Ocean currents redistribute heat around the globe, influencing weather patterns and moderating temperature extremes. This global heat conveyor belt helps to maintain a relatively stable climate.
• Regulation of Atmospheric Gases
  • Carbon Sink: The ocean absorbs approximately 25% of anthropogenic carbon dioxide emissions, acting as a significant carbon sink. This helps to mitigate the greenhouse effect and slow down climate change.
  • Biogeochemical Cycles: Marine organisms play a crucial role in the global carbon cycle, influencing the exchange of carbon dioxide between the atmosphere and the ocean.
• Influence on Weather Patterns
• • Evaporation and Precipitation: The ocean is the primary source of water vapor, which fuels weather systems and influences precipitation patterns.
  • Storm Formation and Intensity: Ocean temperatures and currents can influence the formation and intensity of storms, such as hurricanes and typhoons.

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The Cost of Climate Regulation

• Ocean Acidification: Increased carbon dioxide absorption leads to ocean acidification, harming marine ecosystems, particularly coral reefs and shellfish.
• Disrupted Biogeochemical Cycles: Changes in ocean temperature and chemistry can disrupt marine ecosystems and alter biogeochemical cycles, affecting nutrient availability and productivity.
• Marine Pollution: Pollution from human activities, such as plastic waste and chemical runoff, further stresses marine ecosystems and exacerbates climate change impacts.
• Harm to Marine Ecosystems: Rising sea temperatures, ocean acidification, and pollution threaten marine biodiversity and fisheries, impacting livelihoods and food security.

Marine Carbon Dioxide Removal (mCDR)

• Marine Carbon Dioxide Removal (mCDR) encompasses methods aimed at enhancing the ocean’s natural ability to absorb atmospheric carbon dioxide, mitigating climate change by reducing greenhouse gas concentrations.
• mCDR is not a substitute for emissions reductions but can complement efforts as the world transitions to net-zero emissions.
• It offers potential to address lingering CO₂ burdens and keep warming below 1.5°C if combined with aggressive decarbonisation strategies.
• mCDR techniques include:
  • Biotic (Nature-Based) Solutions: These approaches use natural ecosystems, such as mangroves, seagrasses, and macroalgae, to sequester carbon dioxide with capability of capturing up to 1 billion tonnes of CO₂ annually, with storage durations of hundreds to thousands of years.
  • Abiotic (Engineered) Solution: Techniques involve direct manipulation of oceanic physical or chemical properties for carbon sequestration.
    • Ocean Alkalinity Enhancement (OAE): Adding alkaline substances to seawater to neutralize acidity and form stable bicarbonate or carbonate ions capable of sequestering 1-15 billion tonnes of CO₂ per year.
    • Biomass Burial at Sea: Sinking organic materials, such as kelp or crop residue, into deep ocean layers to sequester carbon. It is capable of sequestering 7-22 billion tonnes of CO₂ annually.
    • Ocean Iron Fertilisation (OIF):  Adding iron to ocean waters to stimulate phytoplankton blooms, which capture carbon dioxide which boosts biological carbon sequestration by enhancing primary product

Risks and Challenges of Marine Carbon Dioxide Removal (mCDR) Techniques

• Ocean Iron Fertilisation (OIF): It risks disrupting marine ecosystems, altering food webs, and depleting oxygen levels in deeper waters. These disruptions may harm biodiversity and compromise the ecological balance of ocean systems.
• Macroalgae Cultivation: Macroalgae cultivation, a biotic approach to carbon capture, involves growing seaweed to absorb carbon dioxide. 
  • While beneficial for removing carbon, decaying biomass from large-scale cultivation can significantly alter the local chemistry of marine environments, potentially leading to unintended ecological consequences.
• Ocean Alkalinity Enhancement (OAE): Despite its promise of scalability, OAE raises significant concerns about its potential impacts on marine biodiversity and ecosystems. 
  • Additionally, the process is energy-intensive, often requiring extensive resources for material production and deployment.
• Challenges in Calibration and Measurement: The vastness and turbulence of open seas make accurate measurement and calibration of carbon removal difficult.
  • Determining how much carbon is captured and remains sequestered poses a major scientific and logistical challenge, undermining efforts to monitor and validate the effectiveness of mCDR techniques.

India’s Untapped Potential in the Indian Ocean

• Strategic Importance: The Indian Ocean, encompassing the Arabian Sea and Bay of Bengal, represents a significant opportunity to address climate change through marine carbon dioxide removal (mCDR).
• Carbon Sequestration Potential:
  • The Indian Ocean could capture 25-40% of marine carbon dioxide through carefully implemented mCDR techniques.
  • Deep ocean currents provide natural pathways for long-term carbon storage.
• Diverse Ecosystems: Rich marine biodiversity supports both biotic solutions (mangroves, seagrasses, and coral reefs) and abiotic solutions (alkalinity enhancement and biomass burial).

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Initiatives to Promote the Role of the Ocean in Climate Action

• Marine Ecosystem Restoration: Programs to restore mangroves, coral reefs, and seagrasses to enhance carbon sequestration and coastal resilience.
  • Example: Mangrove Action Plan and coastal afforestation initiatives.
• Blue Economy Policy: Promoting sustainable use of ocean resources while addressing climate change impacts.
  • Development of ocean-based renewable energy projects like offshore wind and tidal energy.
• Research and Development: Investments in marine carbon capture technologies and ocean observation systems to monitor marine carbon flux.
  • Collaboration with academic institutions and research organizations to develop scalable mCDR solutions.
• Regional Partnerships: Strengthening ties with Indian Ocean Rim Association (IORA) countries to implement shared climate action goals.
• • Leveraging regional expertise in marine conservation and sustainable development.
• Participation in Global Frameworks: Active engagement in initiatives like the United Nations Decade of Ocean Science for Sustainable Development (2021–2030).
  • Collaboration on international research projects to advance marine-based carbon removal.
• Technology and Knowledge Exchange: Partnering with countries experienced in mCDR techniques (e.g., Japan, Australia) for technical assistance and training.
  • Sharing satellite and AI-based tools for marine ecosystem monitoring.

Way Forward

• Awareness Campaigns: Educating the public about the ocean’s critical role in climate mitigation.
• Stakeholder Engagement: Collaborating with local communities, NGOs, and the fishing industry to ensure inclusive and sustainable solutions.
• Capacity Building: Training marine scientists and policymakers in cutting-edge mCDR technologies and governance frameworks.
• Future Prospects: India’s strategic geographical advantage, combined with robust government policies and international collaborations, positions it as a global leader in ocean-based climate solutions.

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