A researcher counts fish swimming around a coral reef at Palmyra Atoll in the central Pacific: Half of all marine life is at risk from acidification. © Los Angeles Times/Getty Images
“How inappropriate to call this planet Earth when it is quite clearly ocean,” science fiction author Arthur C. Clarke once wrote.
But even he could not have foretold the heavy burden our oceans now shoulder from the escalating climate crisis. The oceans absorb over 90% of the heat generated by global warming, produce 50% to 80% of the world’s oxygen and soak up roughly 25% of global carbon dioxide emissions.
Oceans are our greatest ally in combating climate change. However, their waters are rapidly becoming more acidic, especially along coastlines. This will be potentially catastrophic for marine life and the billions of people whose livelihoods depend on it.
Since the preindustrial era, our oceans have become 30% more acidic, the fastest measured change in ocean chemistry in the last 50 million years.
Carbon dioxide is the culprit. Human activities, principally the burning of fossil fuels, have generated an estimated 1.5 trillion tons of CO2 pollution. As the sea absorbs CO2 from the atmosphere, it dissolves to form carbonic acid, increasing oceanic acidity levels.
The effect is not uniform: pH levels in the subsurface waters of the Pacific are lower than the global average, while the coastal waters of northwest Africa and the Pacific seaboard of the Americas now experience CO2-rich waters welling up from the deep ocean.
…
Naoko Ishii, Nikkei Asia, 20 January 2023. Full article.
