Report on Ocean Acidification and Sustainable Development Goals (SDGs)

Introduction

Recent scientific research has confirmed that ocean acidification, driven by escalating atmospheric carbon dioxide (CO₂) emissions, has surpassed safe thresholds across extensive areas of the world’s marine environment. This phenomenon poses significant threats to marine biodiversity and ecosystems, emphasizing the urgent need for enhanced ocean protection and aggressive CO₂ emissions reduction. These findings are critically linked to the achievement of multiple Sustainable Development Goals (SDGs), particularly SDG 13 (Climate Action), SDG 14 (Life Below Water), and SDG 15 (Life on Land).

Key Findings on Ocean Acidification

1. Ocean acidification has exceeded safe limits not only at the sea surface but extends down to 200 meters (656 feet), affecting 60% of the world’s oceans, compared to 40% at the surface.
2. Polar regions and ocean upwelling areas are especially impacted, with significant declines in habitats for calcifying species such as coral reefs, polar pteropods, and coastal bivalves.
3. The acidification process reduces carbonate ion availability, essential for marine organisms that rely on calcium carbonate for their shells and skeletons, threatening marine biodiversity and ecosystem functionality.
4. Ocean acidification acts as an additional stressor alongside climate change-related impacts like marine heatwaves, oxygen depletion, pollution, overfishing, and deep-sea mining.

Implications for Marine Ecosystems and Biodiversity (SDG 14)

• Tropical and subtropical coral reefs have lost approximately 43% of their suitable habitat due to acidification.
• Polar pteropods, vital to marine food webs, have experienced a 61% reduction in suitable habitat.
• Coastal bivalves have lost 13% of their habitat, affecting ecosystem services and fisheries.
• These changes threaten marine biodiversity, with potential cascading effects on global food security and livelihoods.

Urgency for Enhanced Ocean Protection (SDG 14 & SDG 15)

Marine protection efforts currently lag behind terrestrial conservation. However, momentum is growing following the 2025 UN Ocean Conference, which advanced commitments to establish new Marine Protected Areas (MPAs) and ratify the High Seas Treaty aimed at protecting 30% of the world’s oceans by 2030.

• The High Seas Treaty seeks to legally safeguard marine biodiversity beyond national jurisdictions.
• Ratification by 60 countries is required for enforcement; currently, 50 countries have ratified.
• Enhanced protection is essential to build ecosystem resilience against acidification and other stressors.
• Adaptive conservation strategies are needed to identify and protect climate refugia, considering changes in ocean chemistry and temperature.

Addressing the Root Cause: Carbon Emissions Reduction (SDG 13)

Experts unanimously agree that the primary solution to ocean acidification is the drastic reduction of fossil fuel emissions driving atmospheric CO₂ levels. The window to limit global warming to 1.5°C under the Paris Agreement is rapidly closing, with only approximately three years left of the remaining carbon budget.

• Even with immediate emissions reduction, ocean acidification effects will persist for centuries due to ongoing CO₂ absorption by seawater.
• Net zero and net negative emissions strategies, including carbon dioxide removal (CDR) technologies, are necessary to mitigate long-term impacts.
• Emerging geoengineering approaches such as ocean alkalinity enhancement and electrochemical CO₂ removal show potential but require further research to understand ecological consequences.
• Experts caution against large-scale geoengineering methods with uncertain and potentially catastrophic side effects.

Integration with Sustainable Development Goals

• SDG 13 (Climate Action): Urgent climate mitigation actions are critical to reduce CO₂ emissions and limit ocean acidification.
• SDG 14 (Life Below Water): Strengthening marine protected areas and sustainable ocean management will enhance resilience of marine ecosystems.
• SDG 15 (Life on Land): Conservation of coastal and marine habitats supports biodiversity and ecosystem services vital to human well-being.
• SDG 17 (Partnerships for the Goals): International cooperation, such as through the High Seas Treaty and UN Ocean Conference outcomes, is essential for effective ocean governance.

Recommendations

1. Accelerate global efforts to reduce carbon emissions in line with the Paris Agreement targets.
2. Expand and enforce marine protected areas, prioritizing regions vulnerable to acidification and other climate stressors.
3. Support research and responsible deployment of carbon dioxide removal technologies with minimal ecological risks.
4. Enhance monitoring of ocean chemistry changes to identify climate refugia and inform adaptive conservation strategies.
5. Promote international collaboration to ratify and implement the High Seas Treaty and other ocean governance frameworks.

Conclusion

Ocean acidification has crossed critical planetary boundaries, threatening marine biodiversity and ecosystem services fundamental to sustainable development. Addressing this challenge requires integrated actions aligned with the Sustainable Development Goals, focusing on climate mitigation, ocean protection, and international cooperation. Immediate and sustained efforts are essential to safeguard ocean health and ensure the resilience of marine ecosystems for current and future generations.

1. Sustainable Development Goals (SDGs) Addressed or Connected

1. SDG 13: Climate Action
   • The article discusses the urgent need to slash carbon dioxide emissions to mitigate ocean acidification and climate change impacts.
   • It emphasizes the importance of meeting the Paris Agreement target of limiting global warming to 1.5°C.
2. SDG 14: Life Below Water
   • The core focus of the article is on ocean acidification, its impact on marine biodiversity, ecosystems, and the need for enhanced ocean protection.
   • It highlights threats such as pollution, overfishing, deep-sea mining, and marine heatwaves affecting ocean health.
   • References to Marine Protected Areas (MPAs) and international agreements like the High Seas Treaty align with SDG 14 goals.
3. SDG 15: Life on Land
   • While primarily about oceans, the article touches on ecosystem resilience and planetary boundaries, which are linked to broader biodiversity conservation efforts under SDG 15.

2. Specific Targets Under Those SDGs Identified

1. SDG 13: Climate Action
   • Target 13.2: Integrate climate change measures into national policies, strategies, and planning.
   • Target 13.3: Improve education, awareness-raising and human and institutional capacity on climate change mitigation, adaptation, impact reduction, and early warning.
2. SDG 14: Life Below Water
   • Target 14.1: By 2025, prevent and significantly reduce marine pollution of all kinds, particularly from land-based activities, including marine debris and nutrient pollution.
   • Target 14.2: Sustainably manage and protect marine and coastal ecosystems to avoid significant adverse impacts, and take action for their restoration to achieve healthy and productive oceans.
   • Target 14.3: Minimize and address the impacts of ocean acidification, including through enhanced scientific cooperation at all levels.
   • Target 14.5: By 2020, conserve at least 10% of coastal and marine areas, consistent with national and international law and based on the best available scientific information.
   • Target 14.6: Prohibit certain forms of fisheries subsidies which contribute to overcapacity and overfishing, and eliminate subsidies that contribute to illegal, unreported and unregulated fishing.
3. SDG 15: Life on Land
   • Target 15.9: By 2020, integrate ecosystem and biodiversity values into national and local planning, development processes, poverty reduction strategies and accounts.

3. Indicators Mentioned or Implied to Measure Progress

1. Ocean Acidification Levels
   • Measurement of aragonite saturation levels in ocean waters (e.g., 10% or 20% aragonite saturation as safe limits).
   • Percentage of ocean area exceeding safe thresholds for acidification (e.g., 60% of ocean to 200 meters depth).
2. Marine Biodiversity and Habitat Health
   • Decline in suitable habitat for calcifying species such as coral reefs (43% habitat loss), polar pteropods (61% habitat loss), and coastal bivalves (13% habitat loss).
   • Incidence and severity of coral bleaching events.
3. Carbon Emissions and Climate Metrics
   • Global atmospheric CO₂ concentration and emissions levels.
   • Global temperature rise relative to preindustrial levels (e.g., aiming to keep below 1.5°C).
   • Remaining carbon budget for limiting warming.
4. Marine Protection Coverage
   • Percentage of ocean area under Marine Protected Areas (MPAs), with a target of 30% protection by 2030.
   • Ratification status of international agreements like the High Seas Treaty (number of countries ratified).

4. Table: SDGs, Targets and Indicators

Source: news.mongabay.com