Comment le désert va changer la France (plus vite que prévu)

The Sahara Desert has been expanding since 1920, and a projection for 2100 shows Spain covered in sand, with France also facing the threat.

• 300,000 tonnes of sand have already been found in snow-covered regions of the Alps. • Desertification threatens billions of people worldwide.

• Can France truly transform into a desert region? • Are there ways to combat the invasion of sand?

Understand the scale of the phenomenon and explore possible solutions.

• The world's largest desert is Antarctica, followed by the Arctic, then the Sahara in third place. • Only 20% of deserts are composed of sand.

• Aridity index: less than 200 mm of annual precipitation (compared to 500 mm average in France). • Land degradation: erosion, urbanization, overgrazing.

One third of the planet's emerged land is threatened by desertification.

• Climate warming linked to fossil fuels dries out soil through evapotranspiration. • Precipitation becomes rarer and concentrated over short periods (down to -20% in southern France at +4°).

In France, an area equivalent to an entire department disappears under concrete every 7 years, breaking ecological continuities and preventing water infiltration.

• Deep ploughing, monoculture, and massive use of fertilizers and pesticides destroy soil life. • This leads to lack of vegetation, increased runoff, and loss of organic matter.

Without vegetation, soil is exposed to sunlight and no longer retains moisture or nutrients, worsening desertification.

Desertification currently affects 3.2 billion people, and France declared for the first time in 2024 that it is affected by this phenomenon.

In a +4° scenario, most of Spain becomes arid or desert, with 74% of Spanish territory at risk according to the UN (Andalusia, Catalonia).

The Mediterranean basin warms faster than the rest of the world, with increases reaching 6° by 2100 compared to 4° globally.

• Since the 1960s, Spain has pumped its groundwater for water-intensive and profitable crops. • The Almería region produces 80% of vegetables consumed in the European Union.

Aquifer levels are dropping drastically, rivers are drying up, and ecosystems lack resources during droughts or heat waves.

1.4% of metropolitan France's area is already considered desertified, despite appearing spared on maps.

• The Eastern Pyrenees received only 252 mm of rain in 2023 compared to a normal of 507 mm. • The Massif Central could be affected, with farmers already short of hay in 2019 due to drought.

A windy episode already brought Saharan sand to snow-capped mountains in France.

Sand deposited on snow absorbs more heat, accelerating melting, reducing spring water availability, and gradually drying zones.

• In California, a desert zone, rivers are diverted or aquifers are pumped to irrigate and produce fruit and vegetables. • This solution provides temporary relief but worsens the problem, as seen in Spain where excessive irrigation dries out soil.

• China's Great Green Wall, launched in 1978, planted over 66 billion trees across an area equivalent to France. • Only 15% of planted trees survived due to low-resilience monoculture.

• In the 2000s, China strengthened its program with diverse reforestation and grazing bans in sensitive areas. • By 2024, the 3,000 km vegetation ring around the Taklamakan was closed, raising national forest coverage from 10% to over 25%.

The zone, once a CO2 emitter, now captures it, and summer precipitation has doubled, creating a virtuous cycle similar to the Great Green Wall project in Senegal.

• Permanent vegetation cover of soil. • No-till to let the earth rest. • Crop rotation to diversify nutrients.

Healthy soil provides food and materials, purifies water, and regulates climate by storing carbon.

• Support farmers toward an agroecological model. • Choose farmers markets or CSA over greenhouse fruit and vegetables irrigated in Spain.

Facing this systemic problem, each individual action counts like a grain of sand to halt the destruction of life.