As global warming causes more lake heatwaves, species threatened, mass fish die-offs predicted

Unlike those living elsewhere, most lake animals cannot simply move to another habitat once their lake becomes uninhabitable. But since 1970, numbers of freshwater vertebrates, including birds, fish, amphibians, reptiles and mammals, have declined by a staggering 83 percent through the extraction of lake water, pollution, invasive species and disease. Warmer lakes hold less oxygen and lose more water through evaporation, forcing species to live in saltier and less oxygenated habitats. Since warmer surface waters hold more nutrients, climate change could cause an explosion in the number of microscopic algae that live in lakes. As heatwaves proliferate and oxygen levels decline, mass fish die-offs are predicted to double from the 2040s in lakes in the northern hemisphere and increase fourfold in the southern hemisphere from the 2080s onwards.