Increasing evaporation losses from global lakes between 1984 and 2018

Abstract:

Lakes provide a multitude of ecosystem services—including fisheries, recreational uses, transportation, water regulation, and also a means of preserving aquatic biodiversity. Due to their high sensitivity, lakes also act as sentinels of the ongoing global climate change. Increasing evaporative water loss from lakes is one of the most critical consequences of a changing climate for lake systems. However, a global-scale assessment of volumetric evaporation from lakes and the long-term trend is still absent. Here, using Landsat-based water area observations along with a newly developed modeling method for evaporation rate calculation, we quantified the monthly volumetric evaporation from 1.42 million lakes (area ≥ 10⁵ m²) from Jan 1985 to Dec 2018. Our estimates show that long-term average evaporation is 1519±102 km³/year, which is equivalent to 128% of the global consumptive water use. During the 34 years between 1985 and 2018, global lake evaporation has been increasing at a rate of 2.74 km³/year. Depending on locations, such volumetric changes are attributed to either increasing evaporation rates, increasing lake areas, or decreasing lake ice cover. Our results underline the importance of lake evaporation with regard to global hydrological and climatic systems. We anticipate that a warming climate will further increase global lake evaporation, stressing the need for accurate quantification of this phenomenon across scales to mitigate the adverse impacts of climate change.