Emerging Global Ocean Deoxygenation Across the 21st Century

Ocean deoxygenation (i.e., loss of oxygen) due to climate change can result in marine environment deterioration. Here we applied a time of emergence method to detect when and where the signals of oceanic oxygen change would emerge from its internal variability in the epipelagic, mesopelagic, and bathypelagic zones. The results from climate model simulations under low-emission conditions (XGHG) and high-emission conditions (RCP8.5) show that the emergence of deoxygenation is projected to occur earliest and most widespread in the mesopelagic zone. Under the RCP8.5 scenario, more than 72% of the global ocean is projected to experience an emergence of deoxygenation before 2080 for all three vertical zones. Regionally, the emergence of deoxygenation is projected to be widespread below the epipelagic zone of the western North Pacific, North Atlantic, and Southern Oceans before 2080. ToE and the spatial coverage of deoxygenation are both important for fisheries and other marine resources protection.