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Global ensemble projections reveal trophic amplification of ocean biomass declines with climate change


Lotze, HK and Tittensor, DP and Bryndum-Buchholz, A and Eddy, TD and Cheung, WWL and Galbraith, ED and Barange, M and Barrier, N and Bianchi, D and Blanchard, JL and Bopp, L and Buchner, M and Bulman, CM and Carozza, DA and Christensen, V and Coll, M and Dunne, JP and Fulton, EA and Jennings, S and Jones, MC and Mackinson, S and Maury, O and Niiranen, S and Oliveros-Ramos, R and Roy, T and Fernandes, JA and Schewe, J and Shin, YJ and Silva, TAM and Steenbeek, J and Stock, CA and Verley, P and Volkholz, J and Walker, ND and Worm, B, Global ensemble projections reveal trophic amplification of ocean biomass declines with climate change, Proceedings of the National Academy of Sciences of the United States of America, 116, (26) pp. 12907-12912. ISSN 0027-8424 (2019) [Refereed Article]


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Copyright 2019 the authors. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

DOI: doi:10.1073/pnas.1900194116


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.

Item Details

Item Type:Refereed Article
Keywords:climate change, ensemble models, fish, global, trophic cascades
Research Division:Environmental Sciences
Research Group:Climate change impacts and adaptation
Research Field:Ecological impacts of climate change and ecological adaptation
Objective Division:Animal Production and Animal Primary Products
Objective Group:Fisheries - wild caught
Objective Field:Fisheries - wild caught not elsewhere classified
UTAS Author:Blanchard, JL (Professor Julia Blanchard)
UTAS Author:Fulton, EA (Dr Elizabeth Fulton)
UTAS Author:Roy, T (Miss Tilla Roy)
ID Code:144012
Year Published:2019
Web of Science® Times Cited:233
Deposited By:Ecology and Biodiversity
Deposited On:2021-04-14
Last Modified:2021-05-04
Downloads:18 View Download Statistics

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