As water demand continues to rise across Europe, new analysis reveals that more people than previously estimated will face water stress in the coming decades. IIASA researchers working on the EU-Horizon ACCREU project highlight the urgent need for informed adaptation strategies.
Global freshwater resources are under increasing pressure due to over-exploitation and pollution. Water-stressed regions are those where there is severe competition for water resources among households, industries, farmers, and ecosystems. At the turn of the century, over 30 million people in Europe (approximately 7% of the population) lived in water-stressed areas. Population growth, economic development, and climate change will likely exacerbate water stress, yet their projected trends and impacts remain uncertain.
Projecting future water demand and availability is key to informing adaptation policies and guiding investment decisions. As part of the EU-Horizon Assessing Climate Change Risk in Europe (ACCREU) project in which IIASA is one of fourteen consortium members, we recently published a high-resolution projected water demand dataset for Europe. Our findings indicate a significant increase in the number of EU-27 residents living in water-stressed areas in 2060, when compared with prior assessments.
According to a business-as-usual scenario, around 39 million people in EU-27 countries will live in water-stressed areas by the middle of this century, accounting for 9.3% of the population. Our estimates are based on the most recent projections of population counts, urbanization patterns, and gross domestic product (GDP), drawing on the latest revision of the Shared Socioeconomic Pathways (SSP) database.
The model used to develop the annual projections of high-resolution sectoral water withdrawal volumes estimates the water demand as a function of population size, economic activity, and energy use. These projections are then fed into the IIASA Community Water Model (CWatM) to revise water stress estimates. Water stress is the ratio between water withdrawal and availability, where areas with ratios between 20% and 40% experience moderate water stress, and ratios higher than 40% face severe water stress. However, the water stress estimates also consider the impact of upstream withdrawals by different sectors on downstream water availability which adds an additional layer of complexity to the water stress assessment.
According to the new dataset, the number of people living in water stressed areas in the EU will increase by 27% between 2000 and 2060, whereas the previous estimates found the opposite trend of decreasing population living under water stress. The difference between these estimates is especially pronounced in Bulgaria, Hungary, Italy, and Spain, where we see a higher share of the population living under water stress according to the updated dataset (see areas marked in red on the map below). Slight increases are observed in the Netherlands and Portugal (indicated as light pink), whereas France, Greece, and Romania, indicate a reduced share of the population living under water stress (marked in blue). The subnational water stress estimates may be different than the national estimates, especially in countries where the overall water stress is projected to decrease, due to the local context (e.g., population trends and upstream-downstream interactions).
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Europe's updated water withdrawal projections incorporate the latest estimates of key socioeconomic drivers, leading to notable revisions in water stress estimates for major EU countries. These changes happen because population growth, economic development, and urban expansion affect different places in different ways over time. In some cases, increased water withdrawals in upstream countries may intensify water stress downstream. A more comprehensive water stress assessment featuring a broader range of socioeconomic storylines and climate scenarios is underway and is expected to provide critical insights for integrated water resource management and climate change adaptation policies.
Note: This article gives the views of the authors, and not the position of the Nexus blog, nor of the International Institute for Applied Systems Analysis.