Evaporative water loss of 1.42 million global lakes

While the evaporative water loss from global lakes is invisible, the volume is substantial. In recent decades, lake evaporation volume has been significantly increasing due to enhanced evaporation rate, melting lake ice, and expansion of water extent. The evaporative loss from global lakes (natural and artificial) is a critical component of the terrestrial water and energy balance. However, the evaporation volume of these water bodies-from the spatial distribution to the long-term trend-is as of yet unknown. Here, using satellite observations and modeling tools, we quantified the evaporation volume from 1.42 million global lakes from 1985 to 2018. We find that the long-term average lake evaporation is 1500 +/- 150 km(3) year(-1) and it has increased at a rate of 3.12 km(3) year(-1). The trend attributions include an increasing evaporation rate (58%), decreasing lake ice coverage (23%), and increasing lake surface area (19%). While only accounting for 5% of the global lake storage capacity, artificial lakes (i.e., reservoirs) contribute 16% to the evaporation volume. Our results underline the importance of using evaporation volume, rather than evaporation rate, as the primary index for assessing climatic impacts on lake systems.

Automated summary

In recent decades, the evaporative water loss from global lake has significantly increased due to various factors. Using satellite observations and modeling tools, the study quantified the evaporation volume from 1.42 million global lakes from 1985 to 2018 and found that the long-term average lake evaporation is 1500 km(3) year(-1) with a growth rate of 3.12 km(3) year(-1). The increasing evaporation rate, decreasing lake ice coverage, and expanding lake surface area are the main contributors to this trend.