Poleward displacement of coastal upwelling-favorable winds in the ocean's eastern boundary currents through the 21st century

Upwelling is critical to the biological production, acidification, and deoxygenation of the ocean's major eastern boundary current ecosystems. A leading conceptual hypothesis projects that the winds that induce coastal upwelling will intensify in response to increased land‐sea temperature differences associated with anthropogenic global warming. We examine this hypothesis using an ensemble of coupled, ocean‐atmosphere models and find limited evidence for intensification of upwelling‐favorable winds or atmospheric pressure gradients in response to increasing land‐sea temperature differences. However, our analyses reveal consistent latitudinal and seasonal dependencies of projected changes in wind intensity associated with poleward migration of major atmospheric high‐pressure cells. Summertime winds near poleward boundaries of climatological upwelling zones are projected to intensify, while winds near equatorward boundaries are projected to weaken. Developing a better understanding of future changes in upwelling winds is essential to identifying portions of the oceans susceptible to increased hypoxia, ocean acidification, and eutrophication under climate change. Key Points Comprehensive assessment of pressures, temperatures, and coastal upwelling winds in CMIP5 models Poleward shift in distribution of coastal upwelling‐favorable winds projected with climate change Changes due to displacement of high‐pressure systems, not land‐sea surface air temperature contrasts