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Climate change: what is ocean acidification?
- Ocean acidification, described as "climate change's evil twin," is driven by increased atmospheric carbon dioxide (CO2) dissolving in seawater, which lowers pH and threatens marine ecosystems and human livelihoods.
- The ocean's pH has dropped from approximately 8.2 to 8.05 since the Industrial Revolution, representing a 40% increase in acidity, with predictions of a 150% increase by the century's end.
- In 2020, Vanessa O'Brien became the first woman to reach both the summit of Mount Everest and the Challenger Deep (nearly 11,000 meters below the Pacific surface) to collect water samples for acidification research.
- Samples of shelled creatures collected by HMS Challenger in 1875 were compared to modern specimens, revealing that shells have become up to 76% thinner over 150 years due to acidification.
- Early evidence of ocean acidification emerged in Washington State in the early 2000s, where over 75% of oyster larvae died because changing ocean chemistry prevented them from forming shells.
- Dr. Sebastian Henniger identifies ocean acidification as the primary cause of "coral porosis," a condition where deep-sea coral skeletons dissolve, leading to the collapse of entire reef ecosystems that support significant biodiversity.
- Current research at a Scottish lab simulates future ocean conditions by exposing deep-sea coral to acidified, warmer, and lower-oxygen waters, with results on ecosystem collapse timelines expected in autumn 2023.
- In Alaska, the Eyak community reports a decline in salmon size (from 50–100 pounds to 30–50 pounds) and quantity, partly attributed to acidification killing pteropods, a vital food source known as the "potato chips of the sea."
- Pteropods, tiny planktonic snails, are showing signs of shell dissolution globally, posing a critical risk to the food chain and the 40% of the global population reliant on seafood for protein.
- Seagrass and kelp are proposed natural mitigation strategies, capable of capturing carbon 35 times faster than tropical rainforests, though scaling these solutions would require vast ocean areas.
- Heimdall, a West London-based company, developed the world's first ocean-assisted direct air carbon capture plant in Hawaii, capturing 37 tonnes of CO2 per year at a cost of $475 per tonne by using the ocean as an intermediary.
- To counteract one year of current global CO2 emissions with Heimdall's technology, approximately 36 million units of the system would be required, highlighting scalability challenges.
- Experts assert that while localized mitigation is possible, reducing ocean carbon levels is ineffective without simultaneously reducing atmospheric CO2 emissions, calling the current situation an unavoidable "car crash" requiring immediate braking.