Climate change will boost global lake evaporation—with 'extreme' consequences

Climate change will boost global lake evaporation -- with 'extreme' consequences
Credit: Yale University

Global lake evaporation will increase 16 percent by the end of the century as a consequence of climate change, a new Yale study finds. But the specific mechanisms that will drive that phenomenon are not quite what scientists expected.

While it is commonly believed that lake is controlled primarily by incoming solar radiation, the researchers used modeling tools to show that other factors—from shorter ice periods to a "reallocation" of heat energy at lake surfaces—are accelerating the loss of lake water into the atmosphere.

In practical terms this accelerated rate of evaporation over the coming decades will, among other outcomes, trigger stronger precipitation events, researchers say.

According to these findings, published in the journal Nature Geoscience, understanding these complex dynamics will be critical if scientists are to accurately predict the future hydrological response to .

"Typically we focus on the 'top-down' ways that the upper part of the atmosphere triggers feedbacks that enhance warming," said Xuhui Lee, a professor of meteorology at the Yale School of Forestry & Environmental Studies and senior author of the paper. "But if we want to make accurate predictions of the hydrological changes we'll need to understand what's happening at the bottom of the atmosphere, including what's happening at the surface of lakes. Because those changes are driving the hydrological response to climate change."

According to Lee, the same mechanism applies to ocean evaporation, the main source of water for supporting global evaporation.

The lead author of the paper is Wei Wang of the Yale-NUIST Center on Atmospheric Environment, which is jointly funded by Yale University and Nanjing University of Information Science and Technology.

About 85 percent of the world's 250,000 lakes are located in mid- to high latitudes, where water remains frozen for part of the year. But as global temperatures rise many of these lakes will freeze later in the winter and thaw earlier in the spring. This shortened ice period causes a higher absorption rate of solar heat since the open water, which is darker than ice, has a lower albedo. (Light colors reflect more sunlight back into space than dark colors.)

Warming temperatures will also introduce an increase in energy needed to support the process of evaporation—essentially changing how energy is allocated. The adjustment of lake surface temperature to these changes in energy allocation reflects a feedback effect that can further enhance evaporation.

At low altitudes lakes will warm more slowly than the air as climate warms, leading to lower degree of radiation loss that, in turn, allows more energy available for evaporation. On the other hand, at high altitudes lakes will warm faster than air, which result in higher surface radiation loss.

Using a lake simulator model to evaluate lake-atmosphere interactions for all major lakes in the world, from 2005 to 2100, the researchers found that about half of the changes in evaporation were attributable to changes in surface energy allocations and shortened ice periods.

Another critical factor at regional levels is changes in snowmelt. In cold and polar regions, for instance, reduced snowmelt is the second largest contributor to lake evaporation increases.

These hydrological responses to climate change will have profound impacts in regions with many lakes, creating stronger precipitation events as more water evaporates into the atmosphere (what goes up, after all, must come down).

For drier regions these shifts could also present challenges in freshwater resource management, Lee said. To make long-term management decisions, for instance, one must understand how much water will stay in a ; if that predictability is diminished it can make it more difficult to plan for drinking water and agricultural demands.

"In dry climates, the increased rate of evaporation may be even higher," he said. "So in some local regions the question of how you conserve could become an increasingly important question."

Explore further

Study sheds light on lake evaporation under changing climate

More information: Wei Wang et al, Global lake evaporation accelerated by changes in surface energy allocation in a warmer climate, Nature Geoscience (2018). DOI: 10.1038/s41561-018-0114-8
Journal information: Nature Geoscience

Provided by Yale University
Citation: Climate change will boost global lake evaporation—with 'extreme' consequences (2018, May 2) retrieved 25 August 2019 from
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.

Feedback to editors

User comments

May 02, 2018
will this happen after the upcoming glaciation?

May 02, 2018
Will this be before or after the sinking of the Maldives?

May 02, 2018
The researchers are from Yale and they used modeling tools to show... There you have it from an unimpeachable authority.

May 02, 2018
Global PATHOLOGICAL BS will increase 16 percent by the end of the year from the AGW Cult and their Pathological "Science".

It was hotter during the 1930s.

May 02, 2018
You guys can rage alll you want at published science but who really cares? You have no argument and no credibility.

May 03, 2018
Yes, higher rainfall often results in lower lakes..."Extreme" is one of the most overused trigger words in the global warming kook vocabulary.

May 03, 2018
And......back to REALITY

Great Lakes water levels forecast to continue 5-year rise

May 03, 2018
More evaporation results in more clouds, which results in more cooling. What's the issue?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more