10 Alarming Statistics on Ocean Acidification and Its Impact

Imagine this: a world teeming with diverse marine life 🪸 – from coral reefs that burst with color to the countless fish species filling up our oceans. Now, picture a world where these ecosystems are perilously close to irreversible damage. This imminent reality is the sobering result of a phenomenon known as ocean acidification, a critical and often-underestimated environmental challenge we all must confront. 

Ocean acidification, driven primarily by the absorption of excessive carbon dioxide (CO₂) released into the atmosphere, is a change in the chemistry of our oceans. Essentially, when seawater absorbs CO₂, it reacts to form acid-bearing molecules, reducing the available amount of carbonate ions and ultimately, leading to a decrease in the overall pH of the ocean – making it more acidic.

💡 Understanding the urgent and profound impact of ocean acidification is vital for the preservation of our marine ecosystems and, by extension, our very survival. We’re not just talking about the loss of beautiful coral reefs — we’re talking about a monumental shift that could disrupt the very balance of life on Earth.

The magnitude of the problem is alarming, as indicated by compelling statistics. Over the past 200 years, the world’s oceans have absorbed about a third of human-caused carbon emissions, leading to an increase in ocean acidity by nearly 30%. To put this into perspective, this rate of acidification is unprecedented in at least the last 300 million years. This rapid acceleration has serious implications not just for marine life, but also for ecosystems and human livelihoods around the globe. 

Let’s take a close look at the alarming impact of ocean acidification. The facts and figures we’re about to explore show a disturbing change in our marine life – all due to human actions.

1. The Rate of Ocean Acidification

The rate of ocean acidification, a critical environmental issue, has accelerated significantly in recent decades. Between 1950 and 2020, the average pH of the ocean surface decreased from approximately 8.15 to 8.05. This change represents a substantial 26% increase in hydrogen ion concentration in the world’s oceans. It’s important to note that the pH scale is logarithmic; thus, a change of one unit in pH is equivalent to a tenfold change in hydrogen ion concentration. Notably, over a 15-year period from 1995 to 2010, ocean acidity increased by 6% in the upper 100 meters of the Pacific Ocean, from Hawaii to Alaska.

Further emphasizing the severity of this trend, the IPCC Sixth Assessment Report in 2021 revealed that present-day surface pH values are unprecedented for at least the past 26,000 years. The report highlighted that the pH value of the ocean interior has declined globally over the last 20-30 years, with a decline of about 0.017 to 0.027 pH units per decade since the late 1980s​​.

2. Percentage of Carbon Dioxide Absorbed by Oceans

Over the past two and a half centuries, the oceans have played a crucial role in mitigating climate change by absorbing approximately 25% of human-induced carbon dioxide (CO2) emissions. This significant absorption has helped reduce the accumulation of greenhouse gases in the atmosphere, thus slowing the rate of global warming. However, this process also leads to increased ocean acidity, posing threats to marine life and overall ocean health.

In 2020, the land and oceans combined absorbed more than half (54%) of the CO2 emitted into the atmosphere. While beneficial in terms of reducing global warming, this absorption exacerbates ocean acidification. The ongoing monitoring and scientific analysis of ocean carbon fluxes are vital for understanding the dynamics of this significant carbon sink. Such studies help determine whether the ocean’s uptake of CO2 will continue to keep pace with emissions and guide strategies for mitigating and adapting to future changes.

The NOAA’s Global Ocean Carbon Network is instrumental in providing long-term observations of carbon across various spatial and temporal scales, from the sea surface to the ocean interior. This extensive network plays a key role in addressing socioeconomic and scientific questions related to the changing global carbon cycle’s impact on society and the environment. It also offers insights into interannual and decadal changes in oceanic CO2 uptake, essential for assessing the feedback between climate change and the ocean carbon cycle.

Through measurements of temperature, salinity, and pCO2 in surface water and air, the network quantifies the atmospheric CO2 sequestered by the ocean, documents changes in surface ocean carbon chemistry, and evaluates the variability in air-sea fluxes. These observations are critical for providing meaningful projections of future atmospheric CO2 levels​​​​​​​​.

3. Decline in Coral Reef Growth Rates

The decline in coral reef growth rates, primarily due to ocean acidification, poses a significant threat to these vital ecosystems. A comprehensive study by Southern Cross University, analyzing data from the late 1960s to the present, suggests that if the current trend of declining coral growth continues, the world’s coral reefs may stop calcifying around 2054. This projection is based on an analysis of 116 studies from 53 published papers.

The research indicates that global calcification rates of coral ecosystems are declining at an average rate of 4.3% ± 1.9% per year, along with a concurrent reduction in mean coral cover of 1.8% per year. These statistics highlight that not only the loss of coral cover but also the declining health of the remaining coral contribute to reduced global calcification rates. Stress events, such as coral bleaching, significantly impact calcification, even without causing coral death. During stressful times, corals may temporarily reduce calcification as a survival mechanism.

The study encompassed case studies from various global locations, including the Great Barrier Reef, Lord Howe Island, and Western Australia reefs in Australia, as well as reef sites in Japan, Hawaii, the Red Sea, French Polynesia, and Bermuda. It was found that healthy, fast-growing reefs, such as One Tree Island, tend to have high calcification rates, whereas degraded reefs, like Lizard Island, exhibit low calcification rates. However, these repeat surveys of calcification and productivity have been limited to only seven sites globally​​​​​​.

4. Reduction in Marine Biodiversity

Ocean acidification, a result of increased carbon dioxide absorption by the oceans, has profound impacts on marine biodiversity. This process, likened to an “osteoporosis” of the sea, particularly affects shellfish such as oysters and clams, making it difficult for them to build and maintain their shells. This impact extends to other species vital to marine ecosystems, including reef-building corals and pteropods, small snails that are a food source for many species including fish and whales.

Regions like the Pacific Northwest, Long Island Sound, Narragansett Bay, Chesapeake Bay, Gulf of Mexico, and areas off Maine and Massachusetts have been identified as hotspots vulnerable to ocean acidification. This poses a significant risk to the $1 billion U.S. shellfish industry and Alaska’s fisheries, which represent nearly 60 percent of U.S. commercial fish catch and support over 100,000 jobs.

Globally, ocean acidification is causing the weakening of coral structures in the Caribbean, as well as cold-water reefs off Scotland and Norway. The Great Barrier Reef has seen a decline by half in living corals over the past three decades, diminishing fish habitat and the resilience of the entire reef system. Similar threats are observed in Patagonian waters and the Antarctic, where corrosive conditions are dissolving shelled creatures, impacting the food sources for fish, birds, and marine mammals.

More than a billion people worldwide rely on ocean-derived food as their primary protein source, with approximately 20% of the global population getting at least one-fifth of their animal protein intake from fish. Ocean acidification’s effects on marine species could alter food chains and human food supply, impact jobs and economies dependent on fisheries, and even lead to social disruption and conflict. Additionally, acidification may reduce storm protection provided by reefs, diminish tourism opportunities, and affect other benefits derived from healthy marine ecosystems​​​​.

5. Increase in Ocean Acidification Hotspots

Now, let’s move our attention to the geographical regions being profoundly rattled by ocean acidification. It’s startling to see how widespread the issue is, and sadly, certain parts of our blue planet are bearing an excessive brunt. 

The Arctic Ocean is one of the most vulnerable and impacted areas. With excessive absorption of carbon dioxide, its waters are acidifying faster than most of the global oceans. This high susceptibility is due to its cold water temperatures, which absorb carbon dioxide more readily. 

Similarly, the coastal waters of the eastern Pacific, extending from Alaska down to California, are seeing a swift surge in acidity levels. This notorious process, known as Coastal Acidification, is claiming this region. The interaction of carbon dioxide emissions with coastal upwelling is delivering an acidification double whammy to this marine area. 

The Southern Ocean around Antarctica isn’t spared either. It is experiencing a rapid transformation due to the burgeoning carbon dioxide concentration, causing a drastic reduction in calcium carbonate necessary for marine lifeforms like shellfish and corals to survive. 

Further along, projections pinpoint the Western Mediterranean and the Gulf of Mexico as potential new hotspots for accelerated ocean acidification, largely induced by intensifying human activities. 

Our oceans are on the frontlines of an invisible war against increasing acidity. Recognizing these hotspots is crucial in devising strategies for mitigation and adaptation. Now that you’re informed about these troubled areas, what action will you take?

6. Impact on Fisheries and Global Food Security

Climate change significantly impacts fisheries and global food security, with profound economic and nutritional consequences. A study examining over 800 fish species in more than 157 countries revealed that climate change and overfishing impact the availability of essential micronutrients like omega-3 fatty acids, iron, zinc, calcium, and vitamin A from marine fish catches. It is estimated that climate change threatens the supply of these vital micronutrients in 40% of countries, particularly affecting tropical nations such as Malaysia, Cambodia, Indonesia, Timor Leste, Mozambique, and Sierra Leone. These countries are less resilient to disruptions due to their heavy reliance on fisheries for their economies and diets and their limited capacity to adapt​​.

Economically, global fisheries revenues could drop by 35% more than the projected decrease in catches by the 2050s under high CO2 emission scenarios. The global fisheries sector, with official landings estimated at 80-85 million tonnes annually and revenues around USD 100 billion, supports the livelihoods of 660 to 820 million people worldwide. Climate-induced changes in ocean conditions, such as temperature and salinity, are expected to lead to shifts in species distribution and composition, impacting global marine fisheries​​.

The maximum catch potential (MCP) is projected to decrease globally by 7.7% by 2050 under a business-as-usual scenario, with a more significant 10.4% decrease in maximum revenue potential (MRP). These changes are more pronounced in the tropics, where MCP and MRP are projected to decrease by 38% and 33%, respectively. Conversely, regions like the Arctic Ocean may see increases in MRP due to new fishing opportunities from melting sea ice. However, low Human Development Index (HDI) countries, which are heavily dependent on fisheries for food and income, are projected to see substantial decreases in MRP, exacerbating food security issues. These countries, often also affected by declining agricultural yields due to climate change, are less capable of adapting to these changes​​.

The overall economic impact is significant, as fisheries play a crucial role in national economies, especially in low HDI countries. The negative impacts on these economies could be more severe than in countries where fisheries contribute less to the national GDP. Examples of such vulnerable countries include Tokelau, Tuvalu, and the Marshall Islands​​.

7. Economic Loss from Declining Ocean Health

The declining health of the oceans is causing significant economic losses globally. The FAO estimates that around 58.5 million people are employed worldwide in primary fish production, with about 600 million livelihoods at least partially dependent on fisheries and aquaculture. Most of these are in developing countries and involve small-scale, artisanal fishers and fish farmers. However, anthropogenic impacts have led to a situation where the percentage of fishery stocks not within biologically sustainable levels rose from 10% in 1974 to 35.4% in 2019​​.

Illegal, unregulated, and unreported (IUU) fishing significantly affects global fish stocks. A World Bank study suggests that reducing fishing would result in a 40% increase in global landed value, and a sustainable equilibrium for global marine fisheries would require reducing the global fishing effort by 44%. Improved fisheries management and investment in sustainable aquaculture could help restore ocean productivity, generating benefits worth billions of dollars, especially in developing countries​​.

Marine pollution, particularly from plastics, poses another major threat. This pollution impacts economies, ecosystems, food security, and potentially human health. Without proper action, the cost to governments for managing plastic waste between 2021 and 2040 is estimated to reach US$670 billion, with a potential annual financial risk to businesses of US$100 billion by 2040​​.

The maritime economy, encompassing marine shipping, ocean tourism, and offshore energy like oil, gas, and wind, accounts for trillions of dollars in trade and economic activity. Thus, the health of the oceans is crucial for sustaining these vast economic sectors​​.

8. Impact on Plankton Populations

Plankton populations, essential components of marine ecosystems, are experiencing changes due to various environmental factors. A comprehensive global survey of plankton revealed the immense diversity of these organisms, including miniature animals, algae, bacteria, and viruses in the ocean. This diversity is vital as plankton serve as the primary food source for larger marine organisms and play a crucial role in carbon dioxide fixation, with marine phytoplankton responsible for fixing about half of the atmospheric CO2​​​​.

However, the fate of plankton in a warming world remains uncertain. Scientists are still striving to understand how increased ocean temperatures, resulting from greenhouse gas emissions, will affect plankton populations. A study suggested that rising water temperatures could negatively impact these populations by disrupting the natural cycles of nitrogen, carbon, and phosphorus. This disruption poses risks to plankton, as temperature is a key factor in their genetic diversity and community composition​​.

While the exact impact of climate change on plankton is still being studied, the research underscores the significant influence that changing environmental conditions can have on these crucial organisms. Understanding the “normal” state of plankton communities worldwide is a critical step in identifying and responding to any anomalies in the future​​.

9. Effect on Shell-forming Marine Life 

The impact of climate change on shell-forming marine life, particularly through ocean acidification, poses significant challenges to these species. As oceans absorb more carbon dioxide (CO₂), they become more acidic, which hinders the ability of crabs, clams, and other shellfish to develop strong shells. These shells are crucial for their survival, offering protection from predators and environmental hazards. Consequently, increased ocean acidity can lead to the death of these animals​​.

In the northwest Pacific Coast, there have already been instances of isolated shellfish wipe-outs linked to ocean acidity. With global CO₂ emissions continuing to rise, the future may hold even more severe impacts for these shell-forming marine species​​.

Unfortunately, specific statistics detailing the extent of these impacts were not readily available in the sources I accessed. The issue is complex and multifaceted, encompassing various species and regions, making it challenging to quantify in simple statistics.

10. Global Efforts to Combat Ocean Acidification

Global efforts to combat ocean acidification are multi-faceted, involving national, state, tribal, and municipal governments. These entities recognize the relationship between climate change and oceanic transformations, as the absorption of CO₂ and excess heat by the oceans leads to higher temperatures, increased acidification, and reduced oxygen levels. Such changes have detrimental effects on marine life, including oyster die-offs and coral reef bleaching, impacting fisheries, aquaculture, tourism, and marine ecosystems​​.

A significant international initiative is the United Nations Sustainable Development Goal (SDG) 14 Target 3, aimed at minimizing the impacts of ocean acidification through enhanced scientific cooperation. However, it’s noted that SDG 14 is the most underfunded of the SDGs, and there’s a pressing need for dedicated investment to fully realize its potential for sustainable development​​.

The International Alliance to Combat Ocean Acidification (OA Alliance) plays a crucial role in these efforts. It advocates for increased financing for ocean mitigation and adaptation strategies, integrating ocean actions into climate policies, including the creation of Ocean Acidification Action Plans and Nationally Determined Contributions. Additionally, the OA Alliance emphasizes the importance of including indigenous peoples’ knowledge and leadership in response strategies. The Global Ocean Acidification Observing Network (GOA-ON) has launched the Ocean Acidification Research for Sustainability (OARS) program, endorsed by the UN Decade of Ocean Science, to provide necessary observational and scientific information on ocean acidification​​.

Furthermore, the OA Alliance focuses on promoting SDG 14.3 among leaders in public and private sectors and international forums. It supports action plans at the local and domestic levels, targeting carbon emissions reductions, local land-based pollution, and strengthening monitoring and adaptive measures​​.

Protecting Our Oceans

In summary, the data highlights a critical issue: our oceans are in jeopardy due to increasing acidification caused by human activities. This not only impacts marine life but also affects communities and industries worldwide. It’s a call to action for everyone – from everyday readers to policymakers. We all have a role to play in addressing this issue. For individuals, this means being more conscious of our environmental impact and advocating for sustainable practices. For policymakers, it’s about prioritizing environmental conservation and implementing effective policies. Together, through informed choices and collective action, we can help protect and preserve our oceans for future generations.