Rapid progression of ocean acidification in the California current system

Nearshore waters of the California Current System (California CS) already today have a low carbonate saturation state, making them particularly susceptible to ocean acidification. Here, we use eddy-resolving model simulations to study the potential development of ocean acidification in this system up to 2050 under the SRES A2 and B1 scenarios. In both scenarios, the saturation state of aragonite Ωaragis projected to drop rapidly, with much of the nearshore regions developing summer-long undersaturation in the top 60 m within the next 30 years. By the year 2050, waters with Ωarag above 1.5 have largely disappeared and more than half of the waters are undersaturated year-round. Habitats along the seafloor become exposed to year-round undersaturation within the next 20 to 30 years. This has potentially major implications for the rich and diverse ecosystem that characterizes the California CS.