Changes to the Ocean’s temperature and chemistry are driving a possible food and health crisis for many impoverished people in the developing world. These changes will also have profound impacts on the diets and economies of wealthier nations and global economic systems.

Ocean Acidification results from the absorption of excess carbon dioxide in the atmosphere into the Ocean. This excess carbon dioxide principally comes from fossil fuel emissions, and the absorption leads to the lowering of the Ocean’s pH (higher acidity), and the subsequent lack of availability of fundamental building blocks for calcifying organisms. This in turn has far reaching effects on Coral Reef ecosystems and many shellfish species that are both of direct nutritional and economic importance to humans, and form the bases of food webs for several species of fish that many people depend upon for food and income. Pteropods, some forms of plankton, molluscs and crustaceans, are already showing their vulnerability to changes in the Ocean’s acidity. Rising Ocean temperatures and other effects of climate change such as sea level rise and stronger storms are having significant impacts on marine ecosystems as well. Rising Ocean temperatures are leading to the bleaching and spread of infectious diseases within Coral reef ecosystems, as well as the migration of many fish species towards the poles, as they can only survive and breed within specific temperature ranges.

The decline in marine resource availability will have an impact on human health and food security in various ways. The obvious immediate risk is for populations in countries that are most dependent on fish and seafood for a large portion of their nutrition and income. In the poorest and least developed countries the people risk becoming malnourished, as they depend on catching wild fish and seafood for sustenance and for either disposable cash or a barterable commodity to purchase other products like rice. For these people, they have little alternative than to depend upon the Ocean and what it provides them.

A study by the organization OCEANA on the vulnerability of the world’s populations to changes in the Ocean, due to Climate Change and Ocean Acidification, has demonstrated the disastrous consequences these changes could have for many of the world’s poor by the middle of this century. Says author Matthew Huelsenbeck, “Fish and seafood are an important source of protein for a billion of the poorest people on Earth..and about three billion people get 15 percent or more of their annual protein from the sea. Emissions from human activities are changing the ocean’s chemistry and temperature in ways that threaten the livelihoods of those who depend on fish and seafood for all or part of their diets. The changes may reduce the amount of wild caught seafood that can be supplied by the oceans and also redistribute species, changing the locations at which seafood can be caught and creating instability for ocean-based food security, or seafood security.”

The Oceana Study further based its national rankings of future vulnerability on factors like national economic resources, prevalence of population malnourishment and projected population growth. These are on top of the principal foci of the analysis; the susceptibility of a country’s natural resources and fishing industries to future changes in the Ocean due to Climate Change and Ocean Acidification. Unsurprisingly, both small and large tropical  island nations in various parts of the world, such as Comoros, Togo, Maldives, Haiti, Madagascar and Indonesia fill the upper parts of the list. Major nations, including those in wealthy oil-producing countries, are also shown to be vulnerable to the oncoming changes to the Oceans. United Arab Emirates, Iran, as well as Pakistan, Thailand and China find themselves firmly on the vulnerability list. As Huelsenback states in the study, “Many of the high-ranking nations based on climate change indicators are located in the tropics and low latitudes. This reflects the general trend that fish species are predicted to be migrating toward the poles as water temperatures continue to rise. Tropical countries are the most dependent on coral reef fisheries which are severely threatened. Island and coastal nations depend more heavily on fish for protein, especially the poorest nations, increasing their vulnerability.” While some populations are more susceptible to all-out crises than others, the Oceans are vital to all of humanity, and many non-tropical countries such as the United States and the United Kingdom are disproportionately responsible for this mess, so it is up to all the nations of the world to protect this common resource.

The disappearing of fish and seafood stocks could also force the migration to urban centers of large coastal populations. Limited food and economic development brought on by changing Ocean Acidity and rising temperatures would accompany rising sea levels. Possible conflict brought on by fighting for the limited resources would exacerbate the situation. These and other unforeseen pressures will be cited as causes of these mass migrations. The changing of traditional diets based on fish to the consumption of more processed and high-calorie imported foods that accompany an urban existence will take place for many, and associated diseases like diabetes and heart disease will soon follow. This is known as the “Nutrition Transition.”

As a clear example of this harmful transition that has already happened and needs to be avoided in other developing nations that still have diets based on fish and seafood, we can look at the Pacific Island populations of near 10 million people. Traditionally, their diets were fish based, but in the past few decades they have abandoned their traditional diets for more imported and processed foods. Pacific Islanders now have some of the highest rates of nutrient deficiencies, such as Iodine deficiency, which can cause anemia in children and pregnant women. Dietary Iodine comes principally from seafood, and is now put into salt for many populations who no longer eat diets high in seafood, to avoid deficiencies. Pacific Islanders now also have incredibly high rates of obesity and associated non-communicable diseases like diabetes. According to the World Health Organization, “Diabetes prevalence among adults in the Pacific region is among the highest in the world; 47% in American Samoa compared with 13% in mainland USA, and it ranges from 14% to 44% elsewhere in the region.”

Fish and some of its constituent nutrients, such as Omega 3 fatty acids, have themselves been linked to healthful benefits in the prevention of several degenerative diseases, diabetes included, but the results are still inconclusive to this point. Benefits in eating fish can be outweighed by toxins and even plastics that bioaccumulate up the food chain and eventually find their way onto the human dinner plate. With Diabetes, for example, some studies suggest that eating diets high in oily fish and associated Omega 3 can help prevent type 2 diabetes, while others have concluded the opposite, that eating diets high in oily fish are actually harmful to metabolic function and can increase the risk of developing type 2 diabetes. Omega 3 is a polyunsaturated fat, and has been shown in some studies to increase the permeability of cell membranes and metabolism, which should help the metabolism of insulins, and the absorbing of glucose from the blood. The results are inconclusive to this point, however, but are worth monitoring for a world population increasingly at risk for developing diabetes and other obesity-related diseases.

These studies have focused principally on populations in developed nations, however, like the United States and Europe, meaning researchers were studying groups with complex and diverse diets that are often high in other kinds of “unhealthy” foods. When considering populations that are almost entirely dependant on fish consumption, degenerative diseases like heart disease and diabetes are almost nonexistent. Japan, whose traditional diet is high in fish, is famous for historically having very low incidence of heart disease and diabetes (a trend that is changing with changes in their traditional diet to a more “Western” diet). These people that are still dependant on fish and seafood for the majority of their caloric intake can be considered most at risk for health problems associated with declining fish populations.

While fish stocks are declining, and many people who traditionally base their diets on wild caught fish and seafood are at substantial risk for losing much of this cheap and nutritious source of protein and income, the global demand for seafood is expected to continue rising. Many jobs, in developing and developed countries alike, are based on the sectors of either capture fisheries or aquacultures. Combined these two sectors account for nearly one-fifth of the entire world’s animal protein intake, and provide jobs to 600-800 million people, or around 9-12 percent of the world’s population. In many countries, such as Indonesia, Bangladesh and Sri Lanka, these percentages are much higher, as protein intake from seafood can be over 50 % and employ well over 20% of the entire nation’s workforce.

At least in terms of population (not in terms of quantity caught),  the vast majority of people employed in capture-fishing still work for small scale artisanal fishing operations, not large industrial fishing fleets. While many of these small scale fishing operations in developing nations employ environmentally destructive practices, like drift-netting and dynamite-fishing, these issues must be addressed through awareness and regulation. These small scale operations have the best potential for sustainability and are a necessity for national, cultural and individual survival in many developing nations.

Industrial fishing fleets, with their practices of indiscriminate “overfishing,” bottom trawling, massive amounts of “bycatch,” pollution, and more, have long been the cause of destruction for marine ecosystems and the threat of extinction for individual species.  The scale of the operations are often so enormous and unsustainable that it is difficult to find a good justification for these practices from an environmental standpoint (as for human health, wild-caught seafood is still considered by most to be “healthier” and more nutritious than farm/aquaculture-raised, though the bioaccumulation of toxins from anthropogenic pollutants are now putting this in doubt). This is especially true when considering the growth of the controversial aquaculture sector.

Aquacultures, or “fish farms,” are a rapidly growing sector of global food production. To meet the demands of an increasingly carnivorous and growing world population, it’s estimated that total fish production will need to expand from its present output of approximately 165 million tonnes to 185 million tonnes by 2030. The most rapidly growing sector to fulfill this demand has been the Aquaculture, which since 1970 has grown by more than 8 percent per year globally. Carp, Salmon, Tilapia and Catfish are the four most farmed fish, while Shrimp is by far the most commonly farmed crustacean. Oysters, clams and mussels are all commonly farmed molluscs. While aquacultures are providing a sort-of safety net in meeting global protein necessities, as well as consumers desires for cheap prices on seafood, they are not immune to the effects of climate change and Ocean acidification that are threatening wild marine species, and are also in many ways part of the problem. For one thing, farmed fish feed upon fish meal and fish oil, which are supplied by the capture of wild fisheries, predominantly large-scale Industrial fishing fleets. There is also significant pollution created by aquacultures, and their energy input and production output is strikingly inefficient. According to a report by Food and Water Watch, “Aquaculture production also causes significant nutrient-loading events from fish feed and other production inputs. Fish consume only a fraction of their feed, and the rest decomposes in the water. In addition, nutrients from aquaculture sites affect an area 3–9 times the size of the confined aquaculture zone.” Aquacultures are likely a necessity and here to stay in order to feed so many billions of people in the world. This truth is only compounded by the sadly inevitable reality of declining wild seafood stocks. So going forward, aquacultures will both need to adjust to higher temperatures and acidifying waters, and become more sustainable in their demand for wild fish feed and impact on the surrounding environment.

Both capture fisheries and aquacultures are at great risk to the changes being brought on by Climate Change and Ocean Acidity. In the United States, we have already seen large declines in Oyster populations in the Pacific Northwest through periodic “die-offs” over the past decade. It’s believed that negative effects on oyster larvae due to Ocean Acidification could be responsible for these die-offs, which has already cost the industry tens of millions of dollars. Lobster, clam and crab are also feared to be at risk in the near future to similar die-offs.

Many commercial fish in the highly productive arctic regions (fish caught off the coasts of Alaska provide the United States populace with more than 50% of their wild-caught seafood intake), like Salmon and Mackerel, rely on pteropods as a fundamental food source, and pteropod populations are at great risk due to Ocean Acidification. Pteropod die-offs could create a potential ripple effect up the food chain. It’s been estimated that in total, between major productive commercial fishing regions such as the Arctic, Pacific Coast, Gulf of Mexico and North and Southeast Atlantic, the United States could lose above 20 percent of its total capture fisheries potential by 2050 due to Ocean Acidification and Climate Change impacts, meaning a  loss of many millions of dollars and thousands of jobs. Losing such a major source of lean animal protein will also have significant health impacts, as people become more dependant on farmed fish and other forms of industrially-raised animal protein.

What we are facing here is a global problem with a clear cause and implementable solutions. Ocean temperatures are rising principally due to the emissions from the burning of fossil fuels, and Ocean Acidification is happening as a direct consequence of excess carbon dioxide in the atmosphere due to fossil fuel emissions, along with deforestation and other industries like cement making and industrial agriculture. These harmful emissions must be massively cut by regulation or heavy and progressive taxation. Plans to sequester excess carbon in places other than the Ocean, through protecting tropical forests and reforestation for example, must be taken more seriously. And a shift to a renewable and nuclear powered global energy economy, along with greater efficiency across all sectors like construction and transportation, must happen. To alter and perhaps destroy the beautiful and intricate ecosystems and species of our Oceans as a consequence of the indiscriminate, ignorant and controllable behavior of one species, and not even the behaviors of those members of the species that depend most on the riches of the Ocean, would be an absolute tragedy.

Resources and Further Reading

Chomo, Victoria. De Young, Cassandra. “Towards sustainable fish food and trade in the face of climate change.” International Centre for Trade and Sustainable Development (ICTSD). March 2015.

Chu, Jennifer. “Ocean acidification may cause dramatic changes to phytoplankton.” MIT News Office based on study in Nature Climate Change. July 2015.

Doney, Scott. Fabry, Victoria. Feely, Richard, et al…”Ocean Acidification: The Other CO2 Problem.” Washington Journal of Environmental Law and Policy. 2009.

Fabry, Victoria. Feely, Richard. Orr, James. Seibel, Brad. “Impacts of ocean acidification on marine fauna and ecosystem processes.” ICES Journal of Marine Science. April 2008.

Feely, R. Bednarsek, N. et al…”Limacina helicina shell dissolution as an indicator of declining habitat suitability owing to ocean acidification in the California Current Ecosystem.” Proceedings of the Royal Society B. June 2014.

Greger, Michael. “Why Would Eating Fish Increase Diabetes Risk?” July 2015.

“How does Climate Change affect coral reefs?” NOAA.

Huelsenback, Matthew. “Ocean-Based Food Security Threatened in a High CO2 World: A Ranking of Nations’ Vulnerability to Climate Change and Ocean Acidification.” OCEANA. September 2012.

Humphreys, Matthew. “Climate sensitivity and the rate of ocean acidification: future impacts, and implications for experimental design.” ICES Journal of Marine Science. May 2017.

“Ocean Acidification: How CO2 Emissions and False Solutions Threaten Our Oceans.” Food and Water Watch. June 2015.

Parry, Jane. “Pacific islanders pay heavy price for abandoning traditional diet.” World Health Organization. July 2010.

Spalding, Mark. “Ocean Acidification, Seafood and Food Security.” The Ocean Foundation and SeaWeb. Presentation at February 2016 Seafood Summit.

Valdez, A. Menni, C. et al…”Omega-3 fatty acids correlate with gut microbiome diversity and production of N-carbamylglutamate in middle aged and elderly women.” Nature: Scientific Reports. August 2017.