Europe’s water crisis: the situation is more serious than we thought

Researchers estimate that Europe has lost an average of nearly 84 gigatonnes of water per year since the beginning of the 21e century. This is an alarming rate, according to Famiglietti. This is equivalent to approximately the volume of water contained in Lake Ontario, or 5 times the average annual flow of the Colorado River in the Grand Canyon. This size (1 gigatonne corresponds to 1 billion tons of water) is almost impossible for us to catch. However, it is on this scale that climate change is currently operating.

The underlying reason is obvious, he explained. There is too much water in some places, and not enough in others. “Water is the messenger that delivers the bad news of climate change” around the world. Many of these losses are the result of excessive groundwater extraction.

Climate change and the overexploitation of aquifers are closely related. As extreme droughts increase, farmers, industrialists and cities pump more water, from deeper and deeper, to make up for the lack of rain and record heat. After this year’s historic drought, as immortalized on the ancient Bohemian Hunger Stone, the aquifers are not replenished, despite the return of rain.

GRACE and other models are part of an urgent and growing need to improve our understanding of aquifers and how they work, said Alice Aureli, a Paris-based hydrogeologist and head of the transboundary groundwater fair. management for UNESCO’s International Hydrological Program. According to European Commission scientists, the drought in 2022 will be the worst in 500 years. The scale of the water shortage is “alarming even in countries where there is a lot of water,” Aureli continued. “Unfortunately, we only act when we are afraid. »


The first pair of GRACE mission satellites (Gravity Recovery and Climate Experiment), led by NASA and the German Aerospace Center, was sent into orbit in 2002. These satellites work like a pendulum; they track changes in water distribution over time by measuring its gravitational force. The amount of water on Earth remains constant and the fresh water we need to survive is only a small amount of all available water. Unfortunately, climate change and other consequences of human activity (such as draining wetlands, building dams or pumping water from aquifers), can cause significant removal of fresh this water, and thus cause serious events (drying of water points, flooding, etc.).

(Read: Dams, a controversial tool in the fight against climate change.)

The first GRACE mission, which ended in 2017, “gave us important data, such as a map of groundwater depletion in the world”, emphasizes Famiglietti, and emphasizes that man has major influence in changing the distribution of fresh water. It also confirmed to us that mid-latitude areas, including the southwestern United States and much of Europe, are drying, as predicted by the Intergovernmental Panel on climate change (IPCC). This drought is not an event to be feared in the near future; it is currently at work, and spreading faster than the IPCC estimated.

In 2018, the United States and Germany launched the GRACE Follow-On mission, called GRACE-FO, a carbon copy of the original mission. The latter showed little effort had been made to protect the planet’s freshwater reserves, Famiglietti said. “We are on a downward slope and are even starting to sink in some places”, including in Europe.

The new data from the GRACE mission confirms what other computer models have revealed about aquifer depletion, said Marc Bierkens, professor of hydrology at Utrecht University in the Netherlands. He and other modellers have long been sounding the alarm about accelerating groundwater depletion, a result of water consumption by farmers, industry and cities, far exceeding the natural recharge rate of aquifers. .

Working with researchers from the International Groundwater Resources Assessment Center (IGRAC) and Deltares, Bierken’s team also showed that aquifer depletion is contributing to global sea level rise. Most of the fresh water pumped from the ground does not return to the aquifers, but eventually evaporates and becomes rain. It falls directly into the ocean or indirectly onto land, feeding streams and rivers that eventually flow into the sea. Bierken estimates that fresh water is responsible for 10 to 15% of sea level rise. “This quantity is enough to understand where such an increase comes from. »

GRACE and other satellite models are very good at identifying “broad trends” on the continental scale. However, according to Bierken, this quality is also their weakness. In fact, countries and communities cannot ensure the sustainable management of their groundwater without knowing how it changes, whether it is influenced by natural or human factors. How does water recharge local aquifers, move through them, and finally escape? What are the specific agricultural, industrial and urban needs that drive groundwater exploitation? What are the types of soils in question and their depth? Types of plants and trees on the surface? Arrangements that prevent re-infiltration of groundwater?

Bierken and his team are trying to integrate several thousand of these variables into a model of the Earth’s subsoils in the form of grids covering an area of ​​more than one hundred million square kilometers, making it possible to visualize the aquifer located at the bottom. This modeling, which will notably take into account the weather and land use, can make it possible to estimate what water loss can be attributed to certain factors, such as its pumping or climate change. Not only that: it will also make it possible to determine what are the potential solutions to compensate for these losses – by studying the possible effects of restoring wetlands, reducing pumping, or even aquifer recharge projects, for example. .


Whether through satellite images or a grid model, according to Aureli, it is important, to save our basements, to help the population visualize their state. Unlike rivers, where what happens upstream is felt downstream, underground flow is not immediately noticeable, and therefore can be diverted and altered in more subtle and unexpected ways. Since no one can see them, some may also want to adapt the groundwater for the purpose of using it as a personal reserve, and keep it secret.

Because of this mysterious and invisible character, we put the largest reserves of fresh water on the planet for a very long time, explains Aureli. This year’s drought-related water crisis has revealed the urgent need to protect this water to avoid shortages, which have dried up grain crops in Italy and caused the shutdown of nuclear reactors in France, and vital shipping route to Germany.

UN member states regularly meet in the context of major crises: climate change, as happened recently at COP27 in Egypt, or the loss of biodiversity, a main topic of COP15 organized this month in Montreal. However, for nearly half a century, UN members have never been able to come together to discuss water management. When he was 18, Aureli, then a student, accompanied his father, who was also a hydrologist, to the first UN water conference held in Mar del Plata in 1977. At that time, almost no one talked about the water under of land, he explained.

(Read: COP27: “The key is sharing the effort. We must move to an economy that abandons the need for growth and goes for moderation.”)

Everything will change next spring. The UN plans to hold a second major intergovernmental conference on water in New York.. To prepare for this, it organized the UN-Water Summit on Groundwater on December 7 and 8, 2022 at the UNESCO Headquarters in Paris: the aim is to discuss how countries can better share transboundary aquifers. Familglietti presented some of his team’s satellite findings (currently assigned to his colleague Hrishikesh Chandanpurkar and others, for spring publication). He has worked to demonstrate the importance of water in the hope that it will become a favorite topic of COPs and other climate negotiations.

If before, groundwater was shrouded in mystery, “now we have the facts to get at,” explains Aureli.

Developed countries also have solutions at hand, such as ecological restoration, aquifer recharge and water demand management, points out Danish hydrogeologist Karen Villholth, director of Water Cycle Innovation, an established consultancy in South Africa. He gave the example of Denmark, which has halved its water consumption per person, from 200 liters per day in the 1980s to around 100 liters today. The difference is made by increasing the price of water, recycling it and other effective measures.

Groundwater can also be a game-changer for climate justice, says Villholth: it is over-exploited in high-income countries and under-exploited in low-income countries. Rich countries that fight water waste can help low-income countries take advantage of their aquifers to provide basic water supplies for their populations, and develop small businesses.

However, like global warming denial, the myth of groundwater abundance remains entrenched despite mounting evidence. In Europe, just look at Tesla’s first production site on the continent: the Gigafactory Berlin-Brandenburg is located southeast of Berlin, in an area where the groundwater level is decreasing. Last fall, when a reporter asked Tesla CEO Elon Musk about fears the plant was taking water away from local people and ecosystems, he laughed out loud and fired back. that he has “everything wrong”.

“There’s water everywhere here,” he replied. “Do you think it’s like a desert? It’s funny. The rain is strong. »

The factory expansion that was originally planned has been postponed due to this year’s severe drought.

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