Underwater lake heatwaves are on the rise, threatening aquatic life

A view of Lake Superior, one of the Great Lakes. Travis J. Camp/Shutterstock

Lakes are essential to ecosystems, providing freshwater, supporting biodiversity and offering crucial habitat for fish and other aquatic species.

But a recent study by my colleagues and I shows that lakes around the world are warming, not just at the surface, but deep below as well. Subsurface heatwaves in lakes, defined as extreme periods of high water temperature below the surface, are increasing in frequency, duration and intensity.