“Our society has become weakened in relation to water resources”

2023-12-12 18:00:02

Hydroclimatologist, research director at the CNRS and professor attached to the ENS, Florence Habets contributed to the works Final limits. Learning to live in a finite worldtaken from Audrey Boehly’s podcast on planetary boundaries (Rue de l’Echiquier, 240 pages, 22 euros), and Human warmth. 18 responses to the climate threattaken from Nabil Wakim’s podcast for The world (Threshold, 320 pages, 19.90 euros).

A hedge at the edge of a field, in Auvergne, in November 2023. MONIQUE MORIN/BIOSPHOTO

How does climate change affect water resources in France?

The risk of droughts is spreading across the territory and the probability that they will be long is increasing. The one that has lasted for more than a year in the Pyrénées-Orientales, for example, is consistent with the trajectories of climate change. At the same time, extreme rainfall is increasing in intensity. This is one of the certainties of the IPCC (Intergovernmental Panel on Climate Change) report. We are already observing it in France: in fifty years, the heaviest rains have increased by 20% in the Cévennes.

Furthermore, with the decrease in volumes in rivers or groundwater, water quality is affected, because the concentration of pollutants increases. Beyond a certain concentration, distribution must be suspended. In the Seine-Normandy basin alone, 1,200 drinking water collection points were closed between 2000 and 2021, including 11% due to pesticides. We put ourselves in danger by not being able to find good water quality.

Finally, our society has become more fragile with the increase in demand for water. A drought at the end of the Second World War lasted five or six years. At the time, there were fewer residents, and everyone consumed less – running water was rare. If such a drought happened again today, nothing would work.

Is water storage, for example in basins, relevant?

It will not help us during long droughts, where there will be no more water in the soil, lakes or groundwater. If you’ve spent a lot of money storing something that’s becoming scarce, you’re stuck. We must not bet everything on this, we are obliged to work on trajectories of sobriety: learning to do as much with less.

Read the decryption: Article reserved for our subscribers Around megabasins, two visions clash on the sharing of water

What sobriety measures should you adopt?

In households, we can reduce the waste of domestic water, linked in particular to relieving oneself in drinking water. There are alternatives, such as dry toilets or using gray water – from the sink or shower, for example – to flush the toilet. We can also limit watering and irrigation; having a lawn in the South of France is not reasonable. The same goes for agriculture: we must adapt to the environment and not transform it so that it meets the needs of crops that have no place there. Things are progressing: we see a lot more sorghum in the fields. Production such as irrigated corn, on the other hand, may have to be restricted.

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