A quarter of the world’s freshwater fish are at risk of extinction, according to the first comprehensive assessment of the animals by the world’s leading scientific authority on the status of species.

The findings, issued on Monday by the International Union for Conservation of Nature at the U.N. climate summit in Dubai, United Arab Emirates, are part of the organization’s latest update to its Red List of Threatened Species. They came as an array of scientists, advocates and ministers attending the negotiations were urging nations to tackle the global biodiversity crisis in tandem with global warming.

Healthy ecosystems store planet-warming carbon while nurturing wild animals, plants and fungi, providing a double win for climate and biodiversity. If natural areas are destroyed, losses are inflicted on both fronts.

As climate change intensifies, it bears down on wildlife already experiencing staggering declines.

The assessment found that the biggest threat to freshwater fish was pollution, affecting 57 percent of the imperiled species in the group. The pollution comes from fertilizers and pesticides running off farm fields, from sediment clogging up rivers and streams after land has been cleared and from human sewage and industrial waste.