TY - JOUR
T1 - Global ensemble projections reveal trophic amplification of ocean biomass declines with climate change
AU - Lotze, Heike K.
AU - Tittensor, Derek P.
AU - Bryndum-Buchholz, Andrea
AU - Eddy, Tyler D.
AU - Cheung, William W.L.
AU - Galbraith, Eric D.
AU - Barange, Manuel
AU - Barrier, Nicolas
AU - Bianchi, Daniele
AU - Blanchard, Julia L.
AU - Bopp, Laurent
AU - Büchner, Matthias
AU - Bulman, Catherine M.
AU - Carozza, David A.
AU - Christensen, Villy
AU - Coll, Marta
AU - Dunne, John P.
AU - Fulton, Elizabeth A.
AU - Jennings, Simon
AU - Jones, Miranda C.
AU - Mackinson, Steve
AU - Maury, Olivier
AU - Niiranen, Susa
AU - Oliveros-Ramos, Ricardo
AU - Roy, Tilla
AU - Fernandes, José A.
AU - Schewe, Jacob
AU - Shin, Yunne Jai
AU - Silva, Tiago A.M.
AU - Steenbeek, Jeroen
AU - Stock, Charles A.
AU - Verley, Philippe
AU - Volkholz, Jan
AU - Walker, Nicola D.
AU - Worm, Boris
PY - 2019/1/1
Y1 - 2019/1/1
N2 - © 2019 National Academy of Sciences. All rights reserved. While the physical dimensions of climate change are now routinely assessed through multimodel intercomparisons, projected impacts on the global ocean ecosystem generally rely on individual models with a specific set of assumptions. To address these single-model limitations, we present standardized ensemble projections from six global marine ecosystem models forced with two Earth system models and four emission scenarios with and without fishing. We derive average biomass trends and associated uncertainties across the marine food web. Without fishing, mean global animal biomass decreased by 5% (±4% SD) under low emissions and 17% (±11% SD) under high emissions by 2100, with an average 5% decline for every 1 °C of warming. Projected biomass declines were primarily driven by increasing temperature and decreasing primary production, and were more pronounced at higher trophic levels, a process known as trophic amplification. Fishing did not substantially alter the effects of climate change. Considerable regional variation featured strong biomass increases at high latitudes and decreases at middle to low latitudes, with good model agreement on the direction of change but variable magnitude. Uncertainties due to variations in marine ecosystem and Earth system models were similar. Ensemble projections performed well compared with empirical data, emphasizing the benefits of multimodel inference to project future outcomes. Our results indicate that global ocean animal biomass consistently declines with climate change, and that these impacts are amplified at higher trophic levels. Next steps for model development include dynamic scenarios of fishing, cumulative human impacts, and the effects of management measures on future ocean biomass trends.
AB - © 2019 National Academy of Sciences. All rights reserved. While the physical dimensions of climate change are now routinely assessed through multimodel intercomparisons, projected impacts on the global ocean ecosystem generally rely on individual models with a specific set of assumptions. To address these single-model limitations, we present standardized ensemble projections from six global marine ecosystem models forced with two Earth system models and four emission scenarios with and without fishing. We derive average biomass trends and associated uncertainties across the marine food web. Without fishing, mean global animal biomass decreased by 5% (±4% SD) under low emissions and 17% (±11% SD) under high emissions by 2100, with an average 5% decline for every 1 °C of warming. Projected biomass declines were primarily driven by increasing temperature and decreasing primary production, and were more pronounced at higher trophic levels, a process known as trophic amplification. Fishing did not substantially alter the effects of climate change. Considerable regional variation featured strong biomass increases at high latitudes and decreases at middle to low latitudes, with good model agreement on the direction of change but variable magnitude. Uncertainties due to variations in marine ecosystem and Earth system models were similar. Ensemble projections performed well compared with empirical data, emphasizing the benefits of multimodel inference to project future outcomes. Our results indicate that global ocean animal biomass consistently declines with climate change, and that these impacts are amplified at higher trophic levels. Next steps for model development include dynamic scenarios of fishing, cumulative human impacts, and the effects of management measures on future ocean biomass trends.
KW - Climate change impacts
KW - Global ecosystem modeling
KW - Marine food webs
KW - Model intercomparison
KW - Uncertainty
U2 - 10.1073/pnas.1900194116
DO - 10.1073/pnas.1900194116
M3 - Article
C2 - 31186360
VL - 116
SP - 12907
EP - 12912
ER -