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 degrees 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.
1.Dalhousie Univ, Dept Biol, Halifax, NS B3H 4R2, Canada 2.US Environm World Conservat Monitoring Ctr, Sci, Cambridge CB3 0DL, England 3.Univ British Columbia, Inst Oceans & Fisheries, Nippon Fdn Nereus Program, Vancouver, BC V6T 1Z4, Canada 4.Inst Catalana Recerca & Estudis Avancats, Barcelona 08010, Spain 5.Univ Autonoma Barcelona, Inst Ciencia & Tecnol Ambientals, E-08193 Barcelona, Spain 6.Food & Agr Org United Nations, Fisheries & Aquaculture Dept, I-00153 Rome, Italy 7.Univ Montpellier, INSERM, Marine Biodivers Exploitat & Conservat MARBEC, Inst Rech Dev,CNRS, F-34203 Sete, France 8.Univ Calif Los Angeles, Dept Atmospher & Ocean Sci, Los Angeles, CA 90095 USA 9.Univ Tasmania, Inst Marine & Antarctic Studies, Hobart, Tas 7001, Australia 10.Univ Tasmania, Ctr Marine Socioecol, Hobart, Tas 7004, Australia 11.Paris Sci & Lettres Res Univ, CNRS, Ecole Normale Super,Ecole Polytech, Inst Pierre Simon Laplace,Lab Meteor Dynam,Sorbon, F-75231 Paris, France 12.Potsdam Inst Climate Impact Res, D-14473 Potsdam, Germany 13.CSIRO, Marine & Atmospher Res, Hobart, Tas 7001, Australia 14.McGill Univ, Dept Earth & Planetary Sci, Montreal, PQ H3A 0E8, Canada 15.Univ British Columbia, Inst Oceans & Fisheries, Vancouver, BC V6T 1Z4, Canada 16.Ecopath Int Initiat, Inst Marine Sci, Barcelona 08003, Spain 17.Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08540 USA 18.Ctr Environm Fisheries & Aquaculture Sci, Lowestoft Lab, Lowestoft NR33 0HT, Suffolk, England 19.Univ East Anglia, Sch Environm Sci, Norwich NR4 7TJ, Norfolk, England 20.Int Council Explorat Sea, Sci Comm, DK-1553 Copenhagen V, Denmark 21.Scottish Pelag Fishermens Assoc, Heritage House, Fraserburgh AB43 9BP, England 22.Univ Cape Town, Marine Res Inst, Dept Oceanog, ZA-7701 Rondebosch, South Africa 23.Stockholm Univ, Stockholm Resilience Ctr, S-11419 Stockholm, Sweden 24.Inst Mar Peru, Callao 07021, Peru 25.Ecosyst Climate & Ocean Anal, F-75019 Paris, France 26.AZTI Tecnalia, Marine Res Div, Pasaia 20110, Spain 27.Plymouth Marine Lab, Plymouth PL13 DH, Devon, England 28.Univ Cape Town, Marine Res Inst, Dept Biol Sci, ZA-7701 Rondebosch, South Africa 29.Inst Rech Dev, AMAP Res Unit, F-34398 Montpellier, France
Recommended Citation:
Lotze, Heike K.,Tittensor, Derek P.,Bryndum-Buchholz, Andrea,et al. Global ensemble projections reveal trophic amplification of ocean biomass declines with climate change[J]. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA,2019-01-01,116(26):12907-12912