Ocean Deoxygenation Emerges as Earth's 10th Planetary Boundary
Scientists argue aquatic deoxygenation could be Earth’s 10th tipping point, supplementing the existing Planetary Boundaries. Warming temperatures and nutrient runoff are reducing dissolved oxygen across lakes, reservoirs, and oceans, with notable declines such as 40% oxygen loss in midwaters off California since 1960. If widespread, this trend threatens marine life, fisheries, and global climate feedbacks, underscoring the need to cut emissions and curb nutrient pollution to safeguard ecosystems and economies.