Climate Change and Coastal Upwelling Drivers

Given the importance of coastal upwelling to fisheries, coastal ecosystem services, and economic benefits to coastal communities, understanding and projecting the impacts of future climate change on upwelling areas is of significant interest. Coastal upwelling is driven by alongshore winds, which have been hypothesized to increase in eastern boundary upwelling systems (EBUS). However, upper ocean warming is also anticipated to enhance water column stratification, which could limit the efficacy (nutrient flux) of coastal upwelling. Although extensive work has been done on how winds and temperature are changing and projected to change, significant low-frequency climate variability and the poor representation of upwelling in earth system models has prevented a thorough assessment of climate change impacts on these systems. To circumvent these issues, here we synthesize results from a combination of regional and global observations, reanalysis products, and model projections that investigate how the regional drivers of upwelling-favorable winds (land and ocean pressure systems) and stratification (ocean temperature), among other drivers of wind variability, have changed and how they are expected to change in the future. We discuss how these changes might impact the coastal upwelling process and ecosystems in each of the four main EBUS