As waters warm under projected climate changes in the future, tropical regions of the planet will permanently lose hundreds of fish species as they migrate polewards towards cooler seas. Yet, despite the enormous scale of this loss, existing fisheries policies make no mention of this challenge, a new analysis finds.
The researchers on the new study suggest that instead of relying on fisheries agreements, countries should consider climate policies as a way to secure compensation for these losses, in decades to come.
Writing in Nature Sustainability, the researchers analyzed the effects of two climate scenarios on global fishing: a situation where temperatures rise by about 2.4 °C on average, and the worst case or ‘business-as-usual’ scenario in which global temperatures rise by about 4.3 °C on average.
This showed that in warm, tropical seas, there will be the greatest permanent losses, globally, of fish species migrating to cooler waters, while the numbers of new incoming species will be lower than anywhere else in the world. “Climate change is warming the oceans and driving fish in search of colder waters,” explains Kimberly Oremus, lead author on the study and assistant professor at the School of Marine Science and Policy at The University of Delaware. By 2100 under the medium-impact scenario, this means that waters off tropical countries will on average lose 7% of the species that were present there in 2012. Under the worst-case scenario, that leaps to 40%.
Regionally, Northwest African countries are set to lose the highest percentage of species—roughly 6% by 2050, and 30% by 2100 under the medium-impact scenario. That leaps to a 25% loss by 2050, and 58% by 2100 under the high-impact scenario. Declines will also occur in Central America, and the Caribbean. The effects will be most pronounced in tropical island nations that are heavily dependent on fisheries.
This mass exodus could have hugely detrimental effects on jobs, the economy, food security, and culture in these regions, the researchers say. As well as this, they are concerned that as awareness grows of the impending fish exit, countries will feel compelled to rapidly overfish their stocks to cash in on the industry before it disappears. That would, in turn, damage the overall health of global fish stocks.
Yet, when the researchers analyzed 127 publicly-available international fisheries agreements, they found that none of them contained language that considered the effects of climate change on these shifting species ranges, and on fisheries.
The reality is that traditional fisheries policy assumes that fish populations are static and therefore regionally renewable, Oremus explains. “While new research shows that isn’t the case, the policies have yet to adapt,” she says. “That’s the change our paper is calling for.”
Fisheries agreements may not be the right framework for the challenge—but the researchers think a partial solution may lie in climate change policies. These contain language which recognizes that some countries contribute to climate change more than others, and so could be leveraged to compensate nations that are losing fisheries due to global warming. “Climate policies tend to assume that the baseline is changing and some countries may need assistance,” Oremus explains.
For instance, the Warsaw International Mechanism is a piece of climate policy set up in 2013 for the United Nations to address the losses resulting from global warming. The researchers state that while fisheries aren’t an explicit focus in this mechanism, it’s possible that nations could make a case, using the framework, that stock declines represent a loss that deserves compensation. Already, several countries are using such climate policies to seek support and compensation for climate-related migration, caused by land loss and extreme weather events.
Oremus suggests that fisheries losses deserve a place in these conversations, as well: “It’s time to start including fisheries in climate discussions, so we can work on things like compensation and adaptation in addition to conservation.” But of course, fishing losses are just one of many concerns to navigate within climate policies—so entering the fray will be a very competitive process. There are also many unresolved questions over compensation—such as which, if any, countries would be held liable, and how remuneration would unfold.
Yet this complexity, paired with the inevitability of future fisheries loss, is all the more reason to start having these conversations now, the researchers believe. And there’s the threat of overfishing, in the short-term, to consider too. “Tropical countries may stand to gain from working together to bring the problem of fish migration to the table in upcoming climate talks,” Oremus says. “They may also need to work together to incentivize the countries losing species, to conserve them.”