Black, Bryan A.; Sydeman, William J.; Frank, David C.; Griffin, Daniel; Stahle, David W.; García-Reyes, Marisol; Rykaczewski, Ryan R.; Bograd, Steven J.; Peterson, William T. 2014. Six centuries of variability and extremes in a coupled marine-terrestrial ecosystem. Science 345(6203):1498-1502. doi:https://doi.org/10.1126/science.1253209
Reported trends in the mean and variability of coastal upwelling in eastern boundary
currents have raised concerns about the future of these highly productive and biodiverse
marine ecosystems. However, the instrumental records on which these estimates are
based are insufficiently long to determine whether such trends exceed preindustrial limits.
In the California Current, a 576-year reconstruction of climate variables associated with
winter upwelling indicates that variability increased over the latter 20th century to levels
equaled only twice during the past 600 years. This modern trend in variance may be
unique, because it appears to be driven by an unprecedented succession of extreme,
downwelling-favorable, winter climate conditions that profoundly reduce productivity for
marine predators of commercial and conservation interest.