Enhanced heating effect of lakes under global warming

Abstract

Lakes play a crucial role in shaping both local and regional climates through heat exchange with the atmosphere. Amid global climate change, these interactions have undergone significant shifts. However, our understanding of the global heat release from lakes to the atmosphere, and its future trajectory, remains limited. In this study, we investigate changes in global lake heat release patterns and identify an amplified increase in heat release, particularly in mid to high latitudes (>45°N). This amplification is linked with a feedback mechanism, where the reduction in lake ice cover not only reduces the insulating effect between the warmer lake water and the colder atmosphere but also leads to increased heat absorption by lakes. As a result, lakes in mid-high latitudes experience a greater relative increase in heat release, primarily through upward thermal radiation, compared to lakes at lower latitudes with comparable surface water temperature increases. Additionally, seasonal variations in latent heat flux intensify the heat release during warmer seasons compared to colder ones. Future projections suggest substantially greater heat release compared to historical trends.