More Than 90% of Global Aquatic Food Supplies at Risk From Climate Change, Study Says

“Blue foods,” or foods sourced from aquatic environments, are an important dietary component for more than 3.2 billion people on Earth. But the vast majority of global marine food supplies are threatened by climate change, according to a new study. 

The study found that more than 90% of blue foods — including fished and farmed fish, shellfish, algae and plants in both freshwater and marine environments — are vulnerable. These foods include more than 540 freshwater species and more than 2,190 marine species that many people globally depend on for food.

The researchers, who published their findings in the journal Nature Sustainability, evaluated how 17 different stressors, including sea level rise, pesticide runoff and algal blooms, impact quality and quantity of blue foods.

“We have only scratched the surface in our understanding of how environmental stressors are connected, and how they can both negatively impact the production and safety of the resulting blue foods,” Ling Cao, co-lead author and professor at the State Key Laboratory of Marine Environmental Science at Xiamen University, said in a statement. “Understanding the complexity of these stressors, and their cascading impacts, will be essential in developing successful adaptation and mitigation strategies.”

The study identified which countries are most affected by some of the top stressors, finding that blue foods in the U.S. are particularly at risk of invasive species, algal blooms, sea level rise and ocean warming. China, the top blue food producer, is vulnerable to inland eutrophication and severe weather, particularly for its freshwater food supplies. 

The researchers also found that blue foods in marine ecosystems were the most vulnerable to stressors, mainly mercury, ocean warming and acidification. On the other hand, seaweed mariculture showed the most promise of adapting to the stressors and faced the least risks.

In general, though, blue food production is threatened all over the world and on every continent, the study found. 

“Environmental stressors do not care about national borders,” Ben Halpern, co-lead author and professor at UC Santa Barbara and director of the National Center for Ecological Analysis and Synthesis, said in a statement. “Stressors get moved by air, water, species, and humans, connecting land to sea and ecosystem to ecosystem.”

As Reuters reported, 85% of aquaculture production stems from just four countries: China, Japan, India and Vietnam. The study highlighted these countries, as well as small island nations, as top priorities in reducing vulnerability.

Some recommendations in the paper include diversifying types of blue food production, establishing international policies on sustainable blue food production and following the knowledge of Indigenous and local peoples in developing strategies and policies.

Rebecca Short, co-lead author of the study and researcher at the Stockholm Resilience Centre, said, “Although we have made some progress with climate change, our adaptation strategies for blue food systems facing environmental change are still underdeveloped and need urgent attention.”