• Pre-Collegiate Global Health Review

Climate Change’s Lesser-Known Evil Twin: Ocean Acidification and How it Affects Human Health

Aditi Adapala, Lynbrook High School, San Jose, California, USA


It has long been known that there are long-lasting side effects to the increasing levels of carbon dioxide gas in the atmosphere on planet Earth. While the more obvious effects of global warming have been well covered by the media, the devastating effects of ocean acidification are not emphasized. Ocean acidification is the result of excess carbon dioxide molecules in the ocean which can result in changes of the ocean’s chemistry. This causes oceans to become more acidic and harms calcium carbonate structures, which can be considered the backbone of the ocean; they are the building blocks that make up critical ocean structures, from coral reefs to seashells. The loss of carbonate ions has both direct and indirect effects on humans. From a decrease in polyunsaturated fats to its negative effects on the general nutrition we receive, ocean acidification is an unseen threat that the world needs to address.


For the past 100 years, Mother Earth has been under attack by overwhelming pollution, depletion of resources, the release of large amounts of CO2 back into the atmosphere, and much more. While it may not be as well known to the general public, scientists have become more conscious of the effects of ocean acidification. Oceans absorb roughly 30% of the carbon dioxide from the atmosphere (Lebling & Northrop, 2020). Since the industrial revolution, the amount of carbon dioxide in our atmosphere has grown exponentially. Now with all these extra carbon dioxide molecules floating around in the oceans, the ocean has started to change its fundamental chemistry. Contrary to popular belief, ocean acidification will not solely affect smaller island populations.

Figure 1: Projected ocean acidification (Kennedy, 2021).

Ocean acidification has led to fewer lipids and proteins in certain whelk species, which as it goes further up the food chain, leads to a reduction of polyunsaturated fatty acids in the human diet. This is especially concerning because polyunsaturated fatty acids reduce the risk of heart disease, have anti-inflammatory properties, and suppress abnormal heartbeats to encourage better blood circulation (Falkenberg et al., 2020). Oregon State University’s Linus Pauling Institute has conducted several studies showing just how dramatically the presence of unsaturated fats can decrease the chances of cardiovascular episodes. The researchers studied the effects of linoleic acid (LA), the primary source of omega-6 fatty acid on a large group of participants. The study showed a correlation between higher linoleic acid intake and lowered risk of cardiovascular episodes. Specifically, they found it to lower the risk of coronary heart disease events by 15% and lowered the risk of coronary heart disease mortality by 21% (Essential Fatty Acids, 2022).

The unsaturated fats we would lose from ocean acidification not only put us at much greater risk for heart disease but also increase the chances of getting type 2 diabetes (Willett & Hu, 2008). According to the National Center for Biotechnology Information, “evidence suggests that replacing saturated fats and trans fatty acids with unsaturated (polyunsaturated and/or monounsaturated) fats has beneficial effects on insulin sensitivity and are likely to reduce the risk of type 2 diabetes” (Willett & Hu, 2008). Diabetes is the seventh leading cause of death in the world (Centers for Disease Control and Prevention, 2021). The loss of unsaturated fats, which have been proven to reduce the chance of being affected by both chronic illnesses, unequivocally affects the health of those at risk.

One of the most essential poly-unsaturated fatty acids is omega-3 polyunsaturated acids which is something that human bodies cannot produce themselves. Unfortunately, Western diets usually feature high amounts of omega-6 polyunsaturated acids. (Kang, 2011) A high ratio of omega-6 to omega-3 has been shown to lead to various health issues, including cardiovascular diseases, cancer, diabetes, and neurodegenerative diseases (Simopoulos and Cleland 2003). Ocean acidification makes this problem worse and affects the synthesis of omega-3 acids in two ways. Ocean acidification and global warming lead to lower biomass of phytoplankton which are the key synthesizers of omega-3 acids. (Kang, 2011) In addition, type-B Ultraviolet (UVB) radiation has increased due to global warming and ocean acidification, and the radiation inhibits the photosynthesis process phytoplanktons undergo to create omega-3 acids (Kang, 2011). The omega-3 acids that phytoplankton produce move their way up the food chain. Fewer phytoplanktons lead to less omega-3 found in our diets. The reduction of omega-3 fatty acids can also be attributed to ocean acidification destroying parts of the long chains that are initially synthesized. This affects the amounts of omega-3 in their consumers, fish, and in turn, affects the consumer of fish (Kang, 2011). Omega-3 has been shown to dramatically decrease the chances of debilitating diseases. Indeed, government and scientific organizations have strongly recommended incorporating omega-3 in human diets (The Pharmaceutical Journal, 2021).

During the last decade, there has been a focus in the ocean science community to find and prevent the potential impacts of ocean acidification. Programs such as NOAA’s Ocean Acidification program help build relationships between scientists, managers, policymakers, and the public to watch and closely observe the effects the changing ocean chemistry has been having, both economically and ecologically. Ocean acidification is rapidly progressing, and action must be taken to help reverse the damage caused and prevent further harm.


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