Water consumption could double by 2050 in France if global warming intensifies and if current usage trends continue, due in particular to the increase in needs linked to irrigation, estimates Monday January 20, 2025 , a report from France Stratégie. “In ten years, renewable fresh water, that which is renewed through the water cycle, has decreased by 14%. As a result, tensions between uses emerge in certain territories and at certain times of the year.notes France Stratégie.
Work on several scenarios
To carry out this prospective work, the organization relied on three scenarios. The first, called “trend”, is akin to maintaining current consumption habits without changing anything. The second, called “public policies”, assumes the strict application of restriction and adaptation measures already put in place by the government, in particular the National Low Carbon Strategy (SNBC). The third so-called “breakthrough” scenario involves careful use of water.
Climate change will play an essential role in agriculture
He added different projections of global warming, with dry or humid spring-summers, measuring the impact on seven sectors of activity: livestock, irrigation, energy, industry, tertiary, residential and navigation channels.
Agriculture is the sector for which climate change will play an essential role, underlines the report: a reduction in precipitation would lead to “an increase in demand for irrigation water if we want to maintain the same yields”exacerbated by the increase in irrigated areas, underlines Hélène Arambourou, co-author of the report.
The reference year is 2020, for which water consumption – the share of water withdrawn and not returned to the environment – was around 5 billion m3. In the event of global warming of +2.4°C between 2041 and 2060 (one of the IPCC scenarios) with significant droughts, water consumption could go up to double (+102%) between 2020 and 2050 in the “trend” scenario and increase by 72% in the “public policies” scenario. Only the rupture scenario would contain the increase at +10%, with sometimes strong variations depending on the regions and times of the year.
Usage conflicts
Withdrawals, particularly from industry, could stabilize (“trend”) or even decrease (“public policies” or “disruption”), due to the shutdown or modernization of the oldest nuclear power plants. This drop will be mainly concentrated in the Rhône valley.
But only the “disruption” scenario, characterized by energy sobriety and a less significant share of nuclear power, would lead to both a reduction in withdrawals and consumption, according to Simon Ferrière, co-author of the report.
-On the agricultural side, by 2050, demand for irrigation is expected to increase “strongly” and become “majority”. To the “difference in energy production (which returns part of the water to natural environments once reprocessed), irrigation consumes the majority of water withdrawn due to plant evapotranspiration »underlines France Stratégie.
Limited effect of megabasins
Even in the disruption scenario, irrigation-related consumption would increase by 40%, the report's authors explained. And the replacement reservoirs (megabasins) will only have one “limited effect” to contain this increase (-6% during peak consumption).
“Without systemic change” agriculture, “it seems complicated to reduce demand”explains Hélène Arambourou, who cites as levers the amplification of agroecological practices, the improvement of irrigation efficiency and regulation of the development of surfaces and crops requiring irrigation.
With this preponderance of agriculture in withdrawals, water demand will also be more concentrated in the summer months, notes the organization which plans to study the tensions and conflicts of use that this could generate.
The territories most concerned are those already highly irrigated such as the South-West, the lands around the Marais Poitevin or the Charente, in which there are already conflicts of use at certain times of the year.
