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Why Should I Care About Ocean Acidification?

The ocean generates about half of the oxygen we breathe, and it regulates the climate and weather patterns we experience. It is our duty to reduce our carbon footprints before we do harm to our oceans and planet that we cannot come back from. Within the last three hundred years, levels of carbon dioxide (CO2) emissions have drastically increased due to the burning of more fossil fuels for energy. Some people believe we can simply reverse climate change, but once damage is done, it’s permanent. Transportation by car, train, and airplane, electricity, deforestation, and industry (integral parts of our way of life) all emit high levels of CO2. Thirty percent of the carbon dioxide in the atmosphere is absorbed by ocean water. Water and carbon dioxide react to form carbonic acid (H2O + CO2 -> H2CO3), which then dissociates into hydrogen ions and bicarbonate ions (H2CO3 -> HCO3 + H+). Thus, these chemical reactions between carbon dioxide and ocean water lead to a higher level of acidity in the sea. Since the advent of the Industrial Revolution (the period of transition from an agrarian economy to one based on machinery), the pH of surface ocean waters has decreased by 0.1. Although a decrease of 0.1 on a scale of 0 to 14 may seem trivial, the pH scale is logarithmic, meaning the acidity of ocean waters has increased by around 30% in that time.

Human activity is quickly altering ocean chemistry, and marine organisms have a hard time adapting to these changes or migrating to safer habitats at such a fast pace. Marine animals face decreased carbonate availability, but carbonate is vital in forming shells and skeletons of calcifiers out of the mineral calcium carbonate. Increased acidity in the ocean slows the growth of calcium carbonate structures and can even dissolve them in especially harsh conditions. In addition, these calcifying creatures need to expend extra energy repairing or thickening and reinforcing their shells. Marine organisms have to compensate for the elevated acidity levels in seawater to maintain healthy body chemistry. This use of energy detracts from essential growth of muscle and shell. Although marine animals and plants can, in theory, combat and survive heightened acidity levels, this process often comes at a significant cost to their health. In addition, ocean acidification also leads to coral bleaching, destroying coral reefs that protect and house thousands of marine organisms. Increased acidity also poses a threat to larvae’s ability to survive until adulthood because of their small size and lack of development. Heightened levels of acidity in the sea produce a ripple effect: organisms higher up the marine food chain that feed on the organisms more directly affected by pH levels have a decreased food supply.

Ocean acidification not only threatens marine life but also human industries. Over a billion people rely on food caught from the ocean or make a living through fishing, diving, the tourism industry, or transporting goods by boat. Ocean-dependent businesses employ 3 million people and generate $282 billion in the United States alone. Additionally, heat waves, droughts, flooding, and wildfires that come with global warming will undoubtedly cost many lives. At the rate it’s progressing, ocean acidification will have a catastrophic effect on biodiversity, climate, the world’s economy, and the workforce.

We need to take the necessary steps to limit global temperature increase to 2°C this century, the agreed-upon target level for industrialized nations around the world. Then, the average ocean surface pH would fall to about 8.01, 1.5 times greater acidity than levels prior to the Industrial Revolution but still relatively manageable. We can achieve this by balancing the use of fossil fuels and renewable energy sources. However, assuming humanity does not make an effort to reduce emissions, atmospheric carbon dioxide concentrations would increase to 1,000 parts per million (ppm) by 2100, three times the current levels. The global average ocean pH level is predicted to fall to around 7.67 by 2100, a five-fold increase in acidification. Such drastic changes in pH have not occurred within the past 21 million years, and scientists do not know if marine organisms will be able to survive and adapt to such accelerated rates of ocean acidification. This sharp decline in pH will pose a significant threat to marine ecosystems, cost the global economy billions of dollars and millions of jobs, and cause unprecedented natural disasters humanity cannot recover from.

References

What is Ocean Acidification?, PMEL Carbon Program, NOAA, https://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification%3F

How does ocean acidification affect marine life?, Natural History Museum, https://www.nhm.ac.uk/discover/quick-questions/how-does-ocean-acidification-affect-marine-life.html

Effects of Ocean and Coastal Acidification on Marine Life, EPA, https://www.epa.gov/ocean-acidification/effects-ocean-and-coastal-acidification-marine-life

Ocean Acidification, Today and in the Future, Caitlyn Kennedy, Climate.gov, https://www.climate.gov/news-features/featured-images/ocean-acidification-today-and-future

Sources of Greenhouse Gas Emissions, EPA, https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions

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Natasha Matta

Natasha Matta

Interested in all things health equity, social justice, and empowerment.