2), they serve both as sentinels of broader anthropogenic. Verkkoclimate change is one of the most severe threats to global lake ecosystems. Lake surface conditions, such as ice cover, surface temperature,. Verkkowhile there is a general sense that lakes can act as sentinels of climate change, their efficacy has not been thoroughly analyzed. We identified the key response variables. Verkkolakes and streams transport and alter nutrients, contaminants, and energy, and store signals of environmental change from local to continental scales. Verkkowhile there is a general sense that lakes can act as sentinels of climate change, their efficacy has not been thoroughly analyzed. We identified the key response variables. Verkkowhile there is a general sense that lakes can act as sentinels of climate change, their efficacy has not been thoroughly analyzed.