Without healthy soils there is no future: solutions to save them from pollution and overbuilding

“Healthy soils for healthy cities”: this is the theme chosen by FAO for World Soil Day 2025, which is celebrated on 5 December. Under streets, car parks and buildings there is soil capable of filtering water, accumulating carbon, regulating temperatures and supporting biodiversity. When it is covered by concrete, it stops doing so, increasing the risk of floods, heat islands and loss of life, both animal and plant. A city without soil is a more vulnerable city.

Italy, land consumption alarm

According to the ISPRA-SNPA report “Land consumption, territorial dynamics and ecosystem services”, in 2024 almost 84 km² were transformed into artificial surfaces, with a net consumption of 78 km², the highest of the decade (+15.6% compared to 2023). 7.17% of the national territory is now waterproofed, compared to the European average of 4.4%. WWF Italy reports: 20 hectares a day are lost between concrete and asphalt. Coastal and plain areas are the most affected, while in cities heat islands exceed 10°C. Neighborhoods with over 50% tree cover recorded temperatures over 2°C lower, demonstrating how vital urban greenery is.

Protected areas: fragile barriers

Protected areas lose around 81 hectares per year, +16% compared to 2023. The Natura 2000 network follows similar trends. The WWF underlines the urgency of 30×30 and of a national law that stops land consumption and promotes the recovery and regeneration of degraded areas. General director Alessandra Prampolini warns: “Land consumption is the real emergency of our country and must become a strategic priority that can no longer be postponed.”

Urban innovation: de-sealing, green roofs and sponge cities

World Soil Day 2025 pays particular attention to urban soils, highlighting virtuous initiatives that bring land back to the center of the city.

Practices such as de-sealing (the removal of asphalt and concrete), green roofs and the “Sponge Cities” model are already changing the face of many cities around the world.

In Strasbourg, the PerméaSol Project compensates for any new ground cover with de-sealing interventions elsewhere. In Paris, the Coulée verte René-Dumont and in New York the High Line have transformed disused railways into linear parks, creating habitats for insects and birds and reducing heat islands. In China, sponge cities like Shanghai and Wuhan are experimenting with rain garden systems, green roofs and permeable pavements to absorb up to 70% of rainwater by 2030. These examples show that restoring the natural function of soil in cities produces measurable benefits on biodiversity, urban resilience and quality of life.

Urban soils: contamination and biodiversity

City soil is often contaminated by heavy metals (copper, zinc, lead, mercury) and hydrocarbons, compacted by infrastructure, but maintains surprising levels of biodiversity. Studies in Berlin and New York show that green roofs and urban parks host high microbial biomass and springtails, small invertebrates that live in the surface layer of the soil and help decompose organic matter, recycle nutrients and improve soil structure, up to 1.6 times more numerous than in agricultural environments, confirming that urban soil is a precious biological refuge.

The European Directive 2025/2360, published in the Official Journal of the European Union on 26 November 2025, introduces for the first time a unitary regulatory framework dedicated to soil monitoring, its resilience and the management of contaminated sites. This European law establishes clear principles to improve soil health, prevent further consumption and encourage restoration interventions, representing an essential tool for greener and more sustainable cities. Together with the Restoration Law, it introduces principles of land consumption mitigation, restoration of degraded areas and urban de-waterproofing. Regenerating green spaces, creating multifunctional green infrastructures and planning resilient cities are concrete tools to reduce risks of flooding, heat and loss of biodiversity, and to restore vitality to urban soil.