Future ocean conditions can be assessed using present trends in fossil fuel use paired with earth system models. Global earth system models generally do not include the full range of local processes important to coastal ecosystems. Compared to global changes, these coastal processes alter the degree of change observed. Higher resolution models that include local processes driven by the global earth system simulations predict modified changes in carbon stressors than projected by global models.
Future ocean conditions can be assessed using present trends in fossil fuel use paired with...
Review status: a revised version of this preprint is currently under review for the journal BG.
Coastal processes modify projections of some climate-driven stressors in the California Current System
Samantha A. Siedlecki1,Darren Pilcher2,Evan M. Howard3,Curtis Deutsch3,Parker MacCready3,Emily L. Norton2,Hartmut Frenzel3,Jan Newton4,Richard A. Feely5,Simone R. Alin5,and Terrie Klinger6Samantha A. Siedlecki et al.Samantha A. Siedlecki1,Darren Pilcher2,Evan M. Howard3,Curtis Deutsch3,Parker MacCready3,Emily L. Norton2,Hartmut Frenzel3,Jan Newton4,Richard A. Feely5,Simone R. Alin5,and Terrie Klinger6
Received: 17 Jul 2020 – Accepted for review: 03 Aug 2020 – Discussion started: 05 Aug 2020
Abstract. Global projections for ocean conditions in 2100 predict that the North Pacific will experience some of the largest changes. Coastal processes that drive variability in the region can alter these projected changes, but are poorly resolved by global coarse resolution models. We quantify the degree to which local processes modify biogeochemical changes in the eastern boundary California Current System (CCS) using multi-model regionally downscaled climate projections of multiple climate-associated stressors (temperature, O2, pH, Ω, and CO2). The downscaled projections predict changes consistent with the directional change from the global projections for the same emissions scenario. However, the magnitude and spatial variability of projected changes are modified in the downscaled projections for carbon variables. Future changes in pCO2 and surface Ω are amplified while changes in pH and upper 200 meter Ω are dampened relative to the projected change in global models. Within the CCS, differences in global and downscaled climate stressors are spatially variable, and the northern CCS experiences the most intense modification. These projected changes are consistent with source waters lower in oxygen, higher in nutrients, and in combination with solubility-driven changes, altered future upwelled waters in the CCS. The results presented here suggest coastal process resolving projections are necessary for adequate representation of the magnitude of projected change in pH and carbon stressors in the CCS.
Future ocean conditions can be assessed using present trends in fossil fuel use paired with earth system models. Global earth system models generally do not include the full range of local processes important to coastal ecosystems. Compared to global changes, these coastal processes alter the degree of change observed. Higher resolution models that include local processes driven by the global earth system simulations predict modified changes in carbon stressors than projected by global models.
Future ocean conditions can be assessed using present trends in fossil fuel use paired with...