La demande en eau Prospective territorialisée à l’horizon 2050

Industry Overview - The report focuses on the future demand for water in France up to 2050, analyzing water withdrawals and consumption across various sectors including agriculture, energy, industry, residential, and navigation canals [15][16][17] - Three scenarios are considered: a "trend" scenario, a "public policies" scenario, and a "rupture" scenario, each with different implications for water usage and consumption [16][17] - The study is conducted at the scale of 40 watersheds in metropolitan France, providing a detailed territorial perspective on water demand [42][44] Water Demand by Sector Agriculture - Irrigation is the largest consumer of water, with significant variations depending on climatic conditions and crop types [130][131][132] - In 2020, water withdrawals for irrigation amounted to 3,540 million m³, with consumption at 3,040 million m³, primarily concentrated during spring and summer months [161] - The trend scenario projects a 50% increase in irrigated agricultural areas by 2050, while the rupture scenario limits this growth to 12% [82][106] Energy - The energy sector, particularly nuclear power plants, accounts for significant water withdrawals, with 13,800 million m³ withdrawn in 2020, but only 500 million m³ consumed [180] - Nuclear plants with open cooling circuits withdraw significantly more water than those with closed circuits, with some plants withdrawing over 200 m³ per MWh produced [178][179] - The public policies scenario envisions a shift towards renewable energy and modernization of cooling systems, reducing water withdrawals [97] Industry and Tertiary - Industrial and tertiary sectors withdrew water primarily for cooling and production processes, with industrial water demand at 441 m³ per employee in 2020 [189] - The public policies scenario includes measures to reduce water usage in industries, such as improved water reuse and efficiency, aiming for a 30% reduction in water withdrawals in the agro-food sector [98] - Data centers, particularly those using liquid cooling, are expected to increase water demand, with global water withdrawals by major tech companies growing significantly [195] Residential - Residential water usage remains stable in the trend scenario, with slight population growth until 2040 followed by a decline [87] - The rupture scenario introduces significant water-saving measures, including decentralized water reuse and improved efficiency, reducing per capita water withdrawals [111] Navigation Canals - The Seine-Nord canal, under construction, is expected to be operational by 2030, with modernization efforts reducing water withdrawals for canal operations [104][112] Climate Projections and Water Demand - Two climate projections, "yellow" (moderate changes) and "violet" (severe changes), are used to model future water demand under different climatic conditions [70][71] - Under the violet projection, water withdrawals remain stable in the trend scenario but decrease in the public policies and rupture scenarios, with consumption doubling in the trend scenario by 2050 [20][21] - The yellow projection shows a decrease in water withdrawals across all scenarios, with the rupture scenario achieving a 37% reduction in consumption by 2050 [22][23] Key Findings - Irrigation will dominate water withdrawals, especially during dry periods, with significant implications for water resources and ecosystems [32] - The rupture scenario is the only one that manages to keep water consumption close to 2020 levels by 2050, through regulated irrigation growth and agroecological practices [24] - The study highlights the need for detailed local-scale work and stakeholder engagement to address future water demand challenges [17][37]