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A new report by an international team of scientists suggests that marine ecosystems around the globe will suffer greater impacts than previously thought due to the effects of climate change, although strong mitigation measures could help limit these predicted declines.

Led by a researcher at Dalhousie University, the team applied an enhanced suite of global marine ecosystem models from the Fisheries and Marine Ecosystem Model Intercomparison Project (Fish-MIP) to reveal how projected climate change will affect future ocean ecosystems.

Compared with the previous models, the new simulations show a greater decline in the biomass of marine species in the world’s oceans under both strong mitigation and high-emissions scenarios due to elevated warming.

“While our results show worrying trends, we also highlight the importance of better understanding of regional changes, where there remains considerable uncertainty yet there is an urgent need to help support adaptation,” says Derek Tittensor, the Jarislowsky Chair in Marine Ecosystem Forecasting at Dalhousie and lead author of the study.

The findings are of particular relevance as international leaders prepare for the 26th Conference of the Parties to the UN Framework Convention on Climate Change in Glasgow, Scotland, early next month.

Co-author Camilla Novaglio of the Institute for Marine and Antarctic Studies and Centre for Marine Socioecology said it is vital to understand the risks of climate change for marine ecosystems – and the benefits of mitigation. Reducing uncertainty in how marine ecosystems respond to climate change will support more effective adaptation planning.

“Projections of climate change impacts on marine ecosystems reveal long-term declines in global marine animal biomass and show that the impacts on fisheries are unevenly distributed,” says Dr. Novaglio.

“Our simulations show elevated warming and changes in the availability of nutrients and food will create a more marked decline in animal biomass in the world’s oceans than previously assessed.”

Climate change caused by humans is a growing threat to marine ecosystems, with its impacts projected to intensify responses in marine animals, including increased mortality, reduced calcification and changing species distributions, abundance and biomass. Coupled with stressors like overfishing, the societal benefits from the ocean and marine conservation efforts are also under threat.

“It is highly important to build confidence in impacts of climate change for regions because it is at these scales that fisheries, the livelihoods and adaptive capacity of coastal communities need to be considered,” says co-author Dr. Tyler Eddy, a research scientist with the Fisheries and Marine Institute of Memorial University of Newfoundland.

An interdisciplinary team of 36 researchers working across 29 research institutions in seven countries contributed to this important study as part of the Fish-MIP.

Julia Blanchard, IMAS and CMS researcher and Fish-MIP program lead, says the project aims to answer questions about the future of fish and fisheries, seafood supply, marine biodiversity and marine ecosystem functioning.

“Fish-MIP brings together disparate marine ecosystem models so we can better understand and predict the long-term impacts of climate change on fisheries and marine ecosystems, and provide an evidence base that will help to inform fisheries, climate change and biodiversity policy,” says Prof. Blanchard.

Published in Nature Climate Change, the study represents a stepping-stone in the planning of future pathways towards sustainability and a major contribution to the sixth Intergovernmental Panel on Climate Change Assessment Report (IPCC AR6), due for release next year.

Contacts:

Alison Auld
Senior Research Reporter
Dalhousie University
Cell: 902-220-0491
Email: Alison.auld@dal.ca

Dr. Camilla Novaglio
Cell: +61 401 195 879
Email: Camilla.novaglio@utas.edu.au

Prof. Julia Blanchard
Cell: +61 411 106 689
Email: Julia.blanchard@utas.edu.au