Water for the world

06 March 2025

Without water, none of us would exist. H₂O is the elixir of life for humans, plants and animals. But the global demand for water is growing by one percent per year. At the same time, climate change is taking an increasing toll on this precious resource. How can our water supply be secured and improved?

You turn on the tap, and out gushes the water: What seems like such a matter of course in our kitchens and bathrooms cannot by any means be taken for granted everywhere the world. One in four people on our blue planet has no access to safe drinking water. According to the United Nations, half of us – that’s around four billion people – live in regions where water is very scarce for at least one month a year.

In Germany, everyone still has access to enough water, always and everywhere. And yet, the consequences of climate change have long been making themselves felt in Germany, as in other places, with more frequent and heavier rainfall events, rising temperatures and long periods of drought.

The persistent drought between 2018 and 2020 forced agriculture to contend with crop failures, and tinder-dry forests fell victim more easily to the depradations of bark beetles and fires. This was especially true for Brandenburg, one of the German Länder with the most water and, at the same time, the least precipitation. To counteract low water levels in rivers, lakes and groundwater, the state government at the time came up with a low water concept (see also info box) in 2021. The declared aim was to reshape the landscape in Brandenburg, which is designed for ease of drainage, and to control water use in such a way as to avoid water shortages as far as possible. The implementation of the low water concept will take five years to complete, and the project management has been taken over by experts from DMT, a subsidiary of the TÜV NORD Group.

“Our focus is on building up new groundwater reserves: We aim to retain water in the landscape for as long as possible by adapting existing water management, rewetting bogs and moors and ecologically restoring water bodies, among other things, so that water will be able to seep into the soil and continuously replenish the groundwater reservoirs.” This matters so much because it’s groundwater that feeds lakes without inflows and also the drinking water supply, 95 percent of which in Brandenburg is accounted for by water extracted from deep underground.

No part of the world is immune from water stress. What needs to happen to tackle it is obvious to many experts: In industrialised nations, rivers and wetlands must be renaturalised, as is planned in Brandenburg, and water wastage must also be reduced and water reuse promoted. Not only that, but water management infrastructure must be adapted to enable it to withstand long dry periods. According to the UN, in many sub-Saharan countries in Africa, huge groundwater reserves that could provide low-cost and clean water have not yet been tapped. In many developing countries in particular, the health of humans and livestock is intimately connected with improved water purification.

However, experts from the UN are also advocating the use of unusual water resources to counteract the increasing incidences of drought. This includes the more consistent use of rainwater and water from the atmosphere, especially from clouds and fog. There are areas, especially in high mountainous regions, where rain is rare, but fog or high levels of humidity are the order of the day. Pilot projects have therefore been launched in Chile, Bangladesh, Ecuador, Tanzania and Israel to collect the droplets of water of which fog is made up in large nets. In a project in Nepal, seven of these nets have managed to supply a settlement with 75 inhabitants with drinking water all year round.

But the desalination of seawater is energy-intensive and therefore as costly as it is harmful to the climate, at least where it is powered by fossil fuels. In a study, the United Nations University Institute for Water, Environment and Health therefore recommends increasing the use of electricity from the sun or wind. Cheap solar power from 17 newly planned plants is also expected to significantly reduce the costs of desalination in Egypt. In December 2024, the largest fully solar-powered desalination plant ever constructed in Egypt was commissioned on the Soma Bay peninsula.

But the environmental impact of desalination plants will also need to be mitigated in the future. This is because the production of drinking water leaves behind highly concentrated salt brine, which is usually discharged back into the sea along with chemical residues from the production process. Once there, it can destroy microorganisms and lower oxygen levels, thereby endangering coastal ecosystems. The declared aim of researchers at the Fraunhofer Institute for Solar Energy Systems, for example, is to develop and advance more efficient methods of seawater desalination, with fewer chemicals and consistent brine recycling. This will allow populations the world over to quench their thirst from the oceans as sustainably as possible.