The ocean is losing oxygen due to climate change, threatening ecosystems, especially in naturally low-oxygen areas called Oxygen Minimum Zones (OMZs). Using the IPSL-CM6A-LR Large Ensemble, this study identifies when climate-driven changes in OMZ volumes and regional deoxygenation emerge from natural variability. We highlight hemispheric asymmetries due to ocean ventilation and provide model-based estimates for the timing of detectable OMZ evolution.
Anthropogenic climate change is causing ocean deoxygenation, with tropical Oxygen Minimum Zones (OMZs) expanding at their edges since the mid-to-late 20th century, reducing habitable space for marine life despite significant internal variability. This study finds that the response is regionally asymmetric, with OMZ cores expanding in northern tropical oceans but contracting in the south due to increased ventilation, and highlights the complex and uncertain emergence patterns of climate-driven deoxygenation.
