Ocean Acidification: Chemistry and Marine Life Effects

The collapse of shark populations triggers devastating socioeconomic consequences for coastal communities. In Kenya and Tanzania, commercial fish catches declined 60-80% within five years as mid-level predators consumed juvenile fish before they could mature. Tourism suffered equally severely, with Maldives losing $10-20 million annually from shark diving tourism drops of 60-80%. However, conservation interventions demonstrate that recovery is possible. Maldives established a shark sanctuary covering 120,000+ square kilometers, resulting in 10-fold increases in reef shark densities within ten years. Armed naval patrols in Kenya reduced shark bycatch by 80% through enforcement and community education.

Fishery collapses cause cascading effects throughout ocean ecosystems and human communities. The decrease in fish populations reduces species biodiversity across the entire ocean ecosystem, potentially leading to species loss. Economically, collapsed fisheries result in lost income for fishermen and reduced tourism revenue for coastal communities that depend on fishing-related tourism.

A study published in Estuarine, Coastal and Shelf Science evaluated 1,300 exploited marine fish populations across ocean basins and climatic zones. The study found a planet-wide decline in average fishery biomass and systematic widespread overfishing of coastal and continental shelf waters. 82% of populations were below levels that can produce maximum sustainable yields, and 87 populations were in very bad condition with biomass levels at less than 20% of what is needed for sustainable fishing. The greatest declines were found in southern temperate and polar Indian Ocean and southern polar Atlantic Ocean, where populations have declined by over 50% since the 1950s. Bottom trawling is identified as particularly destructive fishing method.

About 1 billion people rely on aquatic resources as their main source of animal protein. Since 1990, global fisheries production has declined. Overfishing leads to restructuring of marine ecosystems where dominant species become minor players ecologically. The collapse of fisheries has dramatic, long-lasting effects on local human populations working in the industry and removes an inexpensive protein source from populations that cannot afford alternatives.

The local population is also losing tourism on top of agriculture and the aquaculture realities that were vital for survival. We are having a big problem with price and it is devastating the fact that those realities are the most devastated. The fisheries are also facing the problem of the reduction in biodiversity in the environment, which is affecting the quantity of the fish and therefore impacting the availability of food. We have problems related to food coming from the seaside, coming from the farming, coming from a number of directions that are decremental to the local population.

Since oceans will continue changing regardless of mitigation efforts, adaptation strategies are necessary. The Taylor Shellfish Hatchery in North America invested $500,000 in monitoring intake water to detect ocean acidification events and developed breeding programs for oysters less vulnerable to acidification. Such short-term monitoring combined with selective breeding represents practical adaptation approaches.

Ocean alkalinity enhancement is a climate solution that involves adding materials like lime to seawater to increase alkalinity, which converts absorbed atmospheric carbon dioxide into stable carbonate salts that sink to the ocean floor and remain sequestered for thousands of years; this approach can simultaneously address ocean acidification while removing past emissions, creating economic opportunities through carbon credit markets, but requires supportive regulatory frameworks and social license from coastal communities to scale effectively.

Key mitigation strategies for ocean acidification include: empowering coastal communities through education and awareness programs; mainstreaming ocean acidification into climate change policies, plans, and investment strategies at community and national levels; building resilience through sustainable fisheries and aquaculture development; accessing climate finance to rebuild or build blue carbon sinks such as mangrove forests; fortifying public and private investment in social, economic, and environmental capital; improving fisheries management; supporting mariculture with seed availability for closed-cycle systems; selecting more resilient species through selective breeding; and developing monitoring and early warning systems for detecting water quality fluctuations.

Two main approaches exist for using oceans to combat climate change: blue carbon ecosystems and ocean alkalinity enhancement. Blue carbon involves conserving and restoring coastal habitats like seagrass beds and salt marshes that naturally sequester carbon. Ocean alkalinity enhancement involves adding alkaline materials like olivine to seawater to neutralize acidity and enhance CO2 absorption. While blue carbon has minimal negative side effects, ocean alkalinity enhancement shows great potential but requires further research on potential ecological consequences.

OSPAR's Northeast Atlantic Strategy addresses ocean acidification through mitigation (blue carbon, considering ocean fertilization and geoengineering), adaptation (research, monitoring, mariculture assessment, early warning systems), and resilience (most of OSPAR's work about reducing pollution and marine protected areas increases ecosystem resilience to new pressures). A key challenge is risk-based decision-making under uncertainty - focusing on known factors, win-win activities, and understanding what can be put aside until more understanding is gained. OSPAR is working on joint assessment and monitoring programs to harmonize approaches across contracting parties for regional assessment of ocean acidification changes.

The Paris Agreement (November 2015) aims to limit global temperature increase to 1.5°C, ratified by 55+ countries responsible for 57% of emissions. Countries must develop national emission reduction policies including deforestation control. The International Whaling Commission's moratorium faces challenges as Japan, Norway, and Iceland continue commercial whaling, opposing Southern Atlantic whale sanctuary proposals defended by Brazil, Argentina, Uruguay, South Africa, and Gabon. These international agreements demonstrate the complexity of global environmental governance.

Key international environmental agreements: (1) 1971 Ramsar Convention (wetland conservation), (2) 1987 Montreal Protocol (controls ozone-depleting CFCs), (3) 1992 Earth Summit (adopted Agenda 21), (4) Kyoto Protocol (reducing greenhouse gases), and (5) Paris Agreement (limiting temperature rise to 1.5-2°C). COP30 in 2025 (Brazil) focuses on climate finance and methane emissions.

Key international environmental agreements include: Stockholm Conference (1972) - first global environmental effort; Rio Earth Summit (1992) - produced Agenda 21 and established CBD, UNFCCC, CCD; COP 1 (1995, Berlin); Kyoto Protocol (1997, Japan) - first legally binding emission reduction agreement; Paris Agreement (2015, France) - aims for 1.5-2°C temperature limit; COP 28 (2023, Dubai) - established $300 billion climate finance goal; COP 29 (2024, Baku) and COP 30 (2025, Belém) continue climate action.

International environmental policy evolved through key conferences and agreements: (1) 1949 UN Conference - first environmental discussions; (2) 1972 Stockholm Conference - first dedicated environmental conference, marking global environmental awareness; (3) 1987 Montreal Protocol - countries committed to reducing CFCs that destroy the ozone layer; (4) 1997 Kyoto Protocol - countries committed to reducing greenhouse gases causing global warming; (5) Rio 92 (Earth Summit) - emphasized sustainable development; (6) Rio + 10 (Johannesburg) - continued sustainable development discussions; (7) COP 21 (Paris Agreement, 2015) - 196 countries committed to limiting temperature increase to 1.5°C, with Brazil setting targets of 37% reduction by 2025 and 43% by 2030. Scientific projections indicate 2°C increase by 2100 could cause 70% species extinction.

The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), signed in Washington DC in 1973, is an international agreement that regulates international trade in endangered species to prevent their extinction, and the EU's Fit for 55 package represents the European Union's commitment to reducing net greenhouse gas emissions by at least 55% by 2030 as part of the European Green Deal.