A new study by EDF and leading scientists shows that tackling sustainable fisheries management and climate change together can result in significant increases of food, fish and economic activity, but nations need to act quickly to realize these gains.
The study details how the world’s oceans have the potential to be significantly more plentiful than today even with climate change, provided good management practices are put in place and warming is held to no more than 2 degrees Celsius, according to the first-of-its kind study published today in the American Association for the Advancement of Sciences’ (AAAS) journal, Science Advances.
The study shows that compared to today, estimated future global outcomes include a $14 billion USD increase in profits, 25 billion additional servings of seafood and 217 million more metric tons of fish in the sea—nearly a third more fish than exist today—, if we can meet the imperative of the Paris Climate Accord and ensure global temperatures don’t rise beyond 2 degrees Celsius. The study cautions, however, that these results depend on implementing fisheries management that addresses climate-driven changes in species productivity and geographical range distribution as well as limiting warming from emissions to that level. Inaction on fisheries management and climate change will mean net losses of fish as the planet’s population grows.
A dozen leading scientists from institutions including the University of California at Santa Barbara (UCSB), Environmental Defense Fund (EDF), National Center for Ecological Analysis and Synthesis and Hokkaido University conducted the research. It is the first study to examine future fishery outcomes under both climate change projections and alternative management approaches, and demonstrates that our oceans can be highly productive for decades to come if we act now to put effective management practices in place.
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Fig. 5 Difference in harvest and biomass under the Full Adaptation strategy in 2100 relative to today for RCP 6.0.
The bubble size corresponds to current MSY, and the colors indicate fishery category based on current biomass and fishing mortality rate relative to BMSY and FMSY, respectively. The fishery categories are defined as follows: Healthy (F/FMSY < 1, B/BMSY ≥ 1), Emerging (F/FMSY ≥ 1, B/BMSY ≥ 1), Recovering (F/FMSY < 1, B/BMSY < 1), and Overfished (F/FMSY ≥ 1, B/BMSY < 1). A transparent bubble indicates a decrease in maximum sustainable yield in 2100 relative to today, whereas a solid bubble indicates an increase (see fig. S2 for results under the other RCPs). MT, metric tons.
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[By 2100, the study shows that compared to today, estimated future outcomes include 25 billion additional servings of seafood].
“The results from this study are surprisingly positive—if we can adopt sustainable fishing policies and keep global warming at no more than 2 degrees Celsius, we can still realize significant benefits to fisheries across the globe,” said Merrick Burden, Senior Economist, EDF Oceans program and an author of the paper. “But these benefits require action and this study serves as a wakeup call to governments that they must change the way that fishing takes place or risk losing a crucial opportunity to secure our food supply for generations to come.”
This study examines potential future outcomes for 915 fish stocks across the world under alternative management and climate scenarios. The authors model climate change’s impact on fishery productivity and geographical range distribution, which affects how many fish are available and where they can be caught, under four climate projections. These range from a global temperature rise of 1 degree Celsius (strong climate mitigation) to a rise of 4 degrees Celsius by 2100 (business-as-usual). For each of these climate scenarios, the authors examine future biomass, harvest and profit under alternative management approaches using a bio-economic modeling approach.
The new research shows that roughly 50% of species examined will shift across national boundaries and nearly all are expected to experience changes in productivity in response to rising ocean temperatures. These changes will present new challenges for fishing nations. The study found that implementation of management practices that account for changes in productivity and geographic range distribution can lead to global gains in profits, harvest and biomass compared to today. These practices include flexible management strategies, including the creation and improvement of existing governance institutions to deal with fish distribution such as multilateral fishery agreements, and responsible harvest policies that account for changing stock productivity.
While improved management may lead to improved global outcomes, the outcomes will vary regionally. The results indicate that future fishery profits are expected to decline in tropical latitudes even with management that fully adapts to the climate challenges. This means equatorial nations, many of which have developing economies and are highly dependent on seafood as a source of food and income, will be hardest hit. And how much planetary warming occurs will make a significant difference on the abundance, harvest and profit from fisheries.
“Even with the right management changes, there will be winners and losers and we have to tackle this head on,” said Steve Gaines, the study’s lead author and Dean of the Bren School of Environmental Science at UCSB. “Success will require not only emissions reductions but also multilateral cooperation and real changes in fisheries management. With our growing global population and the increasing needs for healthy sources of protein, these changes will be critical for meeting the U.N. Sustainable Development Goals.”
The impacts of inaction are also clear. Billions of people rely on fish as an important source of protein, and right now 845 million people face serious malnutrition worldwide, in part due to poorly managed fisheries. If nothing changes, 80 percent of the world’s fisheries will be in serious trouble by 2030. Most fishing nations are not responding fast enough to create change and successful transboundary management programs are relatively rare. But action doesn’t take long to have an impact on some species. Studies have demonstrated that many fisheries can bounce back from overfishing in as little as 10 years’ time under the right policies.
“Climate change is expected to hit hardest in many of the places where fisheries are already poorly managed - things are likely to get a lot worse if we don’t act,” said Christopher Costello, an author of the paper and a professor of environmental and resource economics at UCSB. “We can expect inaction to bring increased conflict and potential overfishing as fish move into new waters along with threats to food security in some of the world’s most vulnerable places.”
“Fishermen will be among the most affected by climate change, and this research confirms what they are already seeing on the water,” said Katie McGinty, Senior Vice President, EDF Oceans program. “The window is narrow, but we have the tools and a clear roadmap to build a future with more fish, more food and more prosperity — if we act now.”
The study did not examine other potential threats from climate change such as ocean acidification, and new ways that species might interact. These threats require further study beyond the scope of this paper.
[The full scientific paper is available at http://advances.sciencemag.org/content/4/8/eaao1378 :
"Improved fisheries management could offset many negative effects of climate change" by Steven D. Gaines1,*, Christopher Costello1, Brandon Owashi1,†, Tracey Mangin1,†, Jennifer Bone1,†, Jorge García Molinos2,3,4, Merrick Burden5, Heather Dennis6, Benjamin S. Halpern1,7,8, Carrie V. Kappel7, Kristin M. Kleisner5 and Daniel Ovando1
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Science Advances 29 Aug 2018:
Vol. 4, no. 8, eaao1378
DOI: 10.1126/sciadv.aao1378
Press Release dated August 29, 2018
Environmental Defense Fund (EDF - www.edf.org), a leading international nonprofit organization, creates transformational solutions to the most serious environmental problems. EDF links science, economics, law and innovative private-sector partnerships. Connect with us on EDF Voices, Twitter and Facebook.
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