Low-income nations risk 30% seafood nutrient loss to climate change: Study

Low-income countries could lose up to 30 per cent of nutrients from seafood due to climate change, researchers say in a study published in the journal Nature Climate Change.

These findings about the loss of nutrients, including calcium, iron, protein and omega-3 fatty acids, were valid in a high emissions and low mitigation scenario, the researchers from the University of British Columbia (UBC), Canada, said.

The nutrient loss may be restricted to 10 per cent, however, should the world meet the Paris Agreement targets of limiting global warming to 1.5 to 2 degrees Celsius, they said.

"Low-income countries and the global south, where seafood is central to diets and has the potential to help address malnutrition, are the hardest hit by the effects of climate change," said first author William Cheung, professor and director of the UBC Institute for the Oceans and Fisheries (IOF).

The researchers used predictive climate models on historical fisheries and seafood farming databases to make future projections about the quantities of key nutrients in seafood.

Focussing on the four nutrients plentiful in seafood and important to human health, the researchers found that the availability of these nutrients peaked in the 1990s and stagnated to the 2010s, despite increases provided by farming seafood, and from fishing for invertebrates such as shrimp and oysters.

Looking to the future, the availability of all four nutrients from catches is projected to decrease, they found.

Further, the nutrient calcium was the hardest hit at a projected decline of about 15 to 40 per cent by 2100 under a low and high emissions scenario, respectively, they said.

Omega-3 is expected to see an approximately five to 25 per cent decrease, they said, adding that these declines were largely driven by decreases in the amounts of pelagic fish available for catch.

From the tropical waters of generally lower income nations, such as Indonesia, the Solomon Islands and Sierra Leone, the availability of all the four nutrients are projected to decline steeply by the end of the century under a high emissions scenario, the researchers found, compared to minimal declines in higher income, non-tropical waters, such as those of Canada, the US and the UK.

Globally, the researchers projected that seafood-sourced nutrient availability would decrease by about four to seven per cent per degree Celsius warming.

For lower-income countries across the tropics including Nigeria, Sierra Leone, and the Solomon Islands, the projected decline was two to three times this global average at nearly 10 to 12 per cent per unit of warming, they said in their study.

"The primary reason for this is climate change, which is also a significant threat to seafood farming, leaving us with a growing nutritional deficit," said co-author Muhammed Oyinlola, a postdoctoral fellow in the UBC's department of zoology.

"This research highlights the impact of every degree of warming. The more we can reduce warming, the fewer risks to marine and human life," said Cheung.