Water stress : a vital challenge

2.3 billion people now live in areas without sufficient quantities of water to meet their needs all year long. Driven, among other things, by global warming, water stress continues to spread worldwide. In addition to reducing access to drinking water, water stress has a deep impact on farming and food security, disrupts industrial activities, and poses a threat to biodiversity. It has created a huge, ever-shifting challenge, which will call on resources from both public- and private-sector sectors.

It may seem counterintuitive to say so, but fresh water is actually relatively scarce. It accounts for just 2% of the water on earth (in lakes, rivers, glaciers and wetlands), vs. 97% in the oceans and seas and 1% in subsurface water tables. This material reality contrasts with humans’ constantly increasing water use. Global water consumption rose six-fold in the 20th century, while the global population merely tripled during that same period¹.

According to a report by the World Resources Institute (WRI)² , 25 countries are currently experiencing “extremely high” water stress, i.e., their water consumption has exceeded their water resources by over than 80% during more than one month per year. The Middle East and North Africa are the hardest hit regions (with 83% of the population exposed), but few regions have been spared. A WWF³ report found out that water stress affects 20% of Europe’s surface area and 30% of its population.
As 70% of fresh water is used in farming⁴, water restrictions affect crop yields and hence, indirectly, food security. Regions subject to high water stress, such as some parts of Africa and south Asia, are experiencing spectacular fluctuations in water availability. This has caused spikes in food prices, which, in some extreme cases, can cause famines.
22% of fresh water use is by industry⁵ – energy, manufacturing, textiles, mining, and so on. Each of these sectors uses heavy amounts of water and is likely to be impacted by water crises.

Water stress, a multifactor phenomenon

Water stress results from a combination of factors, starting with urbanisation and climate change. According to a report in Nature⁶, the global urban population facing water shortages is expected to rise from 933 million in 2016 to between 1.7 and 2.4 billion in 2050 (i.e., from one third of the global urban population to almost half). The number of large cities exposed to water shortages is expected to increase from 193 to 284, including from 10 megalopolises to 20. These figures come against a backdrop in which, between 1950 and 2020, the global urban population rose from 0.8 billion to 4.4 billion, with the prospect of reaching 6.7 billion by 2050 (i.e., more than 68% of the global population)⁷. Urbanisation naturally has huge implications on water, including increased and concentrated demand for household and industrial uses in particular, changes in hydraulic cycles (i.e., the increase in impermeable surface area and paving over of vegetation), worsening water quality due to the nature of industrial and domestic pollution, and so on. Combined with intensive farming, soil artificialisation harms water infiltration and the refilling of water tables⁸.

Meanwhile, global warming is making an active contribution to water stress. One consequence of the increased number of extreme weather phenomena, such as flooding, hurricanes, droughts, etc. is to undermine the quality of water sources, thus making water stress even worse⁹. And higher land temperatures cause changes in the water cycle itself by exacerbating evaporation and disrupting the distribution, quantity and quality of available water¹⁰. These are major changes that impact individuals, entire ecosystems, and manufacturing activities. Moreover, climate change also affects water needs for various uses, such as irrigation.

How to address water stress issues

How to meet this key challenge for humanity ? There are many ways to limit water stress. This is a global, amorphous challenge requiring coordination between the public sector (at the national, regional and most local levels) and private-sector actors likely to alter their practices in order to reduce their water use or develop innovative solutions for addressing the source of the problem directly.

As the 6^th Sustainable Development Goal (SDG) deals directly with water, the United Nations held a major global conference on this issue in March 2023. Conference participants heard a key figure often – that to ensure universal access by 2030, current levels of investment would have to be at least tripled¹¹. At a more regional level, in Europe, the Organisation for Economic Cooperation and Development (OECD) estimates that the European Union will have to invest 90 billion euros¹² by 2030 to ensure uniform distribution of water, to combat water stress and to reduce leakage in distribution systems. More than two thirds of metropolitan areas experiencing water stress could remedy it by investing in their infrastructures¹³.

Some possible solutions come from nature itself – restoring streams and wetlands, enhancing resilience to extreme weather phenomena, and so on. There are real reasons for hope, such as the projects supported by the French Development Agency (AFD), with two successes¹⁴ : in Qixian, China, using aquatic plants to filter urban wastewater and supply wetlands with water; and near Dakar, Senegal, using nature to protect water resources and enhance refilling of water tables (refilling water tables and rehabilitating retention ponds, reforestation, stone lines, small filtering dikes, etc.). Another key solution: transitioning from conventional agriculture to agroecology, i.e., introducing practices such as ground cover, agroforestry, etc.) that limit the consequences of aridity on production.

In urban areas, a wide range of solutions is already available to combat water shortages, including use of subsurface water, increased storage of water in reservoirs, transferring water between reservoirs and enhanced efficiency of water use. As fresh water becomes scarcer, a series of promising technologies is emerging not just to filter water but also to eliminate contaminants and open the door to reusing wastewater, sewage, or even seawater. Desalinisation technologies, smart irrigation systems, wastewater management, storage of rainwater, modelling, etc. More broadly, innovation could be an essential source of leverage in providing sustainable solutions.

Beyond these solutions, which are being developed by cutting-edge actors and will require massive investment, all organisations will have to transform their management of, and impact on, water. A remarkable development in this area is the Corporate Sustainability Report Directive (CSRD), which enters force on 1 January 2024 and requires large European companies to disclose a series of water use indicators, including consumption, water withdrawals, use of marine resources, etc. This is yet another example of how everyone at every level can transform awareness into actual deeds.

¹ http://wrsc.org/attach_image/global-water-consumption-1900-2025
² https://www.wri.org/insights/highest-water-stressed-countries
³ https://www.wwf.fr/sites/default/files/doc-2023-09/Water%20scarcity_report_v7.0.pdf
⁴ https://donnees.banquemondiale.org/indicateur/ER.H2O.FWAG.ZS
⁵ https://donnees.banquemondiale.org/indicateur/ER.H2O.FWAG.ZS
⁶ https://www.nature.com/articles/s41467-021-25026-3
⁷ United Nations (UN). 2018. 2018 Revision of World Urbanization Prospects. https://population.un.org/wup/ (2018).
⁸ https://www.wwf.fr/nos-champs-daction/secheresse-comprendre-pour-agir
⁹ https://www.unicef.org/stories/water-and-climate-change-10-things-you-should-know
¹⁰ https://www.ucsusa.org/resources/water-and-climate-change
¹¹ https://www.letemps.ch/monde/penuries-deau-se-generalisent-lonu-craint-une-crise-mondiale-imminente
¹² https://www.oecd.org/environment/financing-water-supply-sanitation-and-flood-protection-6893cdac-en.htm
¹³ https://www.nature.com/articles/s41467-021-25026-3
¹⁴ https://www.afd.fr/fr/actualites/3-projets-innovants-pour-preserver-les-ressources-en-eau