As El Niño cooks Pacific, Calif. scientists warn ocean losing oxygen

Key Points:

• Scientists from UC San Diego’s Scripps Institution of Oceanography warn that climate change is causing a significant loss of dissolved oxygen in global oceans and freshwater, approaching an "unsafe space" with potentially irreversible ecological impacts.
• Since the 1960s, the ocean has lost about 2% of its oxygen content due primarily to human activities like burning fossil fuels, leading to consequences such as mass fish kills, coastal dead zones, and impaired health of aquatic life.
• The study highlights that warming waters, exacerbated by events like marine heatwaves and El Niño, reduce oxygen levels, affecting marine ecosystems along California’s coast and beyond.
• Researchers propose adding dissolved oxygen conditions to the planetary boundaries framework, which defines safe limits for Earth's critical processes, aiming to raise awareness and prompt global policy action on ocean deoxygenation.
• Experts in the field support this inclusion, emphasizing that recognizing deoxygenation as a planetary boundary is crucial for protecting aquatic ecosystems and maintaining Earth's life-support systems.