Regionally, multi-model mean changes in primary production show generally similar patterns of large declines in the North Atlantic and the western equatorial Pacific, while in the high latitudes, primary production consistently increases in CMIP5 and CMIP6 by 2100 . In the Indian Ocean and subtropical North Pacific, which were regions of consistent NPP decline in CMIP5 projections , the regional declines are reduced in magnitude, less spatially extensive and are typically less robust in CMIP6. Further assessment of simultaneous changes in processes such as nutrient advection, nitrogen fixation, the microbial loop and top-down grazing pressure  are required to fully understand the regional primary production response in CMIP6 . Given the regional variations in the estimates of primary production changes and the uncertainty in the representation of the dominant drivers, there remains low confidence in the projected global decline in NPP.
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report