“In ten years, fresh water has decreased by 14%”: due to climate change, water consumption in France could double by 2050

The water consumption could double by 2050 in France yes global warming intensifies and if current usage trends continue, particularly due to the increase in needs linked to irrigation, estimates Monday a report from France Stratégie.

This report was commissioned from fall 2023 by the Prime Minister of the time, Elisabeth Bornea few months after the implementation of the Water Plan intended to limit the consumption of this resource which is expected to become rarer due to climate change.

Already, “in ten years, fresh water renewable, that is to say 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 Strategy by presenting his work.

To carry out this prospective work, the organization responsible for evaluating public policies relied on three scenarios:

• The first says “trend” is akin to maintaining current consumption habits without changing anything.
• The second baptized “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).
• Finally a third scenario “breakup” implies careful use of water.

She 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 canals.

L’agriculture is the sector for which climate change will play an essential role, underlines the report: a reduction in precipitation would generate “an increase in demand for irrigation water if we want to maintain the same yields”, exacerbated by the increase in irrigated surfaces, underlines Hélène Arambourou, co-author of the report.

The reference year is 2020, for which water consumption, that is to say the share of water taken and not returned to the environment, was around 5 billion cubic meters.

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 policy” scenario, the report indicates. 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 should increase “strongly” and become “the majority”. And unlike energy production (which returns part of the water to natural environments once reprocessed, editor's note), irrigation consumes the majority of the water withdrawn due to plant evapotranspiration. underlines France Stratégie.

Even in the disruption scenario, consumption linked to irrigation would increase by 40%, the authors of the report explained Monday during a press briefing. And replacement reservoirs (“mega-basins”) will only have a “limited effect” in containing this increase (-6% during peak consumption).

“Without systemic change” in 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 development of areas and crops requiring irrigation.

With this preponderance of agriculture in the withdrawals, the demand for water will also be more concentrated on the summer months which are traditionally the hottest and where the resource is constrained, notes the organization which plans to study in a future report 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.