Our drinking water evaporates, lakes dry up

Lakes around the world are drying up and our drinking water is evaporating. New research reveals that more than half of the world’s largest lakes and reservoirs have lost a lot of water over the past 30 years. The research on drying up lakes was published in the journal Science.

Our lakes contain almost 90% of the liquid fresh water and they are irreplaceable sources of drinking water, irrigation and energy. They are also a vital living environment for animals and plants. About a quarter of the world’s population lives in the basin of a drying lake.

Climate change has been causing the water level in many lakes to fall structurally for decades. But more causes have been discovered. The water level in the lakes fluctuates in response to natural fluctuations in rainfall and snowfall, but is increasingly influenced by human activity.

That became clear after examining satellite measurements of nearly 2,000 of the world’s largest lakes and reservoirs, scattered around the planet. Together they account for 95% of the total water storage in lakes on earth. More than half of them have lost significant amounts of water. That loss can be attributed to both human activities and climate change, the report said.

Multiple causes for drying up

The fact that so many lakes are drying up does not have the same cause everywhere. Climate change is causing extra evaporation in many areas. This happens in warm regions, but also in the polar region. There it is due to the disappearance of ice, which exposes the surface of the water to the warming air.

If lakes shrink, it could also contribute to drying out of the surrounding watershed, the study said, increasing evaporation and causing the lakes to deteriorate more quickly.

Unsustainable water consumption and wastage are other major causes of lake drying up.

In reservoirs there is another effect: because more and more sediment washes into the reservoirs, the volume decreases and they can store less water. And that process can also increase as a result of climate change. Such as due to the increase in forest fires, as a result of which the soil is less well retained and is washed away into reservoirs.

All of these changes can have cascading effects. These cause a decrease in water quality, an increase in toxic algal blooms and a loss of biodiversity.

Also increase, but often the wrong one

Of course there are also places where the amount of water in lakes is actually increasing. These are mostly lakes in less populated areas, including areas in the northern Great Plains of North America and the interior of the Tibetan Plateau. Where melting glaciers fill the lakes, this often creates new risks for the people living downstream. And water that collects far from civilization can hardly be used as drinking water and for agriculture.