Ocean Acidification

Syllabus: GS3/ Environment

Context

• A recent study has revealed that ocean acidification has breached its planetary boundary, posing grave threats to marine ecosystems and global climate stability.

What is Ocean Acidification?

• Ocean acidification refers to the ongoing decrease in the pH of Earth’s oceans, caused by the uptake of carbon dioxide (CO₂) from the atmosphere. 
• When CO₂ dissolves in seawater, it forms carbonic acid, which lowers ocean pH and reduces calcium carbonate levels – essential for many marine organisms.

Planetary Boundary Breach

• Planetary boundaries are thresholds beyond which the Earth’s vital systems may no longer maintain a stable environment.
• The study finds that by 2020, the average global ocean conditions had already fallen 20% below pre-industrial calcium carbonate saturation, crossing the safe threshold for acidification.
• At 200 metres below the surface, 60% of global waters had breached the “safe” limit for acidification.

Impacts of Ocean acidification

• Calcifying Species Affected: Corals, oysters, mussels, and pteropods (sea butterflies) are most vulnerable.
  • Acidification weakens shells and skeletons, reduces reproduction, slows growth, and increases mortality.
• Fisheries and Livelihoods: Decline in fish nursery grounds affects food security and economic stability of coastal communities.
• Tourism Sector: Coral reef degradation affects tourism and recreational diving industries.
• Climate Feedbacks: Damage to ocean ecosystems like plankton may affect carbon sequestration capacity of oceans. This could amplify global warming over time.
• Social impacts: Climate-linked migration and livelihood loss may increase geopolitical tensions. Rising unemployment in coastal sectors may trigger social unrest.

Initiatives to Tackle Ocean Acidification

• Global Ocean Acidification Observing Network (GOA-ON): GOA-ON is a collaborative international network of 367 members from 66 countries, aimed at enhancing the monitoring and understanding of ocean acidification across estuarine, coastal, and open ocean systems.
• UN Decade of Ocean Science for Sustainable Development (2021–2030): Proclaimed in 2017 by the United Nations General Assembly, it aims to reverse the decline the ocean health through;
  • Stimulating scientific research, technological innovation, and policy-relevant knowledge.
  • Supporting countries to achieve SDG-14 (“Life Below Water) and broader climate resilience.
• Intergovernmental Oceanographic Commission (IOC) of UNESCO: Under its Global Ocean Observing System (GOOS), it supports real-time ocean monitoring including pH and CO₂ measurements.
• Blue Carbon Initiatives provides research, policy advice, and financing mechanisms to promote blue carbon strategies globally.
  • Blue Carbon refers to the carbon stored in coastal and marine ecosystems such as mangroves, salt marshes, and seagrasses.

Way Ahead

• Policy and Governance: Mainstream ocean acidification into national climate and ocean policies.
  • Prioritise Marine Spatial Planning and Integrated Coastal Zone Management.
• Local Adaptation and Conservation: Protect and restore resilient ecosystems, such as mangroves and seagrasses.
  • Implement Marine Protected Areas (MPAs) in regions of high vulnerability.

Concluding remarks

• Ocean acidification is not just a marine problem, it is a multi-dimensional crisis affecting biodiversity, economies, food systems, and climate resilience. 
• Its silent but accelerating pace demands urgent and coordinated policy responses globally and nationally.

Source: Guardian