Soil sealing or soilsurface sealing is theloss of soil resources due to thecovering of land forhousing,roads or otherconstruction work.[1] Covering or replacing thetopsoil withimpervious materials likeasphalt andcement as a result ofurban development and infrastructure construction paired withcompaction of the underlying soil layers results in the mostly irreversible loss of relevant soilecosystem services.[2][3][4] The global rise in population has heightened the need for soil sealing, which in turn leads to thedegradation of land.[5] Sealed land is a serious form of land take (use of land specifically for building settlements, roads, and businesses).[6][7] Soil sealing and land take together leads to the complete loss of soil functions, including its biological, physical and chemical properties.[8]
Replacing natural soil with man-made surfaces greatly affects the process ofwater infiltration. These artificial surfaces don't allow water to seep through as easily as soil does, leading to increasedsurface runoff.[9] Additionally, sealing the soil for underground construction alters water movement, further diminishing the soil's natural ability to purify water.[9][10] In cities, having lots of heat-absorbing concrete and asphalt but not enough cooling vegetation createsheat islands effect.[9][11]
Using human-made materials to cover soil significantly affects its ability to provide essential services like food production.[12] This occurs when fertile agricultural land is converted into buildings and houses.[13] Countries with rapidly growing populations and economies are experiencing notable loss of agricultural land due to development.[9][14]
Soil sealing affects the soil's function as a natural habitat.[9] By completely covering the uppermost layer of soil with man-made substances, it creates fragmented habitats for localbiodiversity. Consequently, this leads to soilbiodiversity loss.[9][15][16] Further, these impacts worsen with a decrease in the soil's carbon and nitrogen content, as well as itsrespiration rate.[17]
Soil's intangible benefits such as spiritual connection, learning, and feeling like we belong to this place, are at risk because land take and soil sealing for urban projects are removing recreational spaces in city centers.[18][19] The impact on cultural services becomes apparent when people worldwide are willing to invest more money in homes located in areas with natural surroundings.[20][21]
A complete soil unsealing process involves entirely removing any human-made materials like asphalt and cement that obstruct the soil's natural functions, thereby restoring its ability to perform its natural processes.[24] There is very limited research about the process of soil unsealing.[9] Due to mostly irreversible losses, soil unsealing is very difficult. However, by following some steps soil unsealing is feasible.
Transforming urban, barren, or previously used dumping soils into spaces for urban parks, green roofs, and gardens. However, it's essential that the soil is thoroughlydecontaminated before any such use to ensure the safety of the environment and the health of those who will be using these spaces.[9] This technique aligns with a European research project in urban planning that emphasizes minimizing construction in green areas and reusing existing industrial sites known asbrownfields.[25]
Removing sealed surfaces or buildings to offset the environmental impact of upcoming new urban projects. This approach is employed in theWalloon Region andGermany, where the "no net land take" principle ensures that urban development plans do not result in a net increase in land usage.[26][27]
^Prokop, Gundula (2011).Overview of best practices for limiting soil sealing or mitigating its effects in EU-27 : final report. Luxembourg: Publications Office.ISBN978-92-79-20669-6.OCLC870622049.
^Pannicke-Prochnow, Nadine; Albrecht, Juliane (2024), Ginzky, Harald; De Andrade Corrêa, Fabiano; Dooley, Elizabeth; Heuser, Irene L. (eds.), "Unsealing: Benefits, Potentials, Legal Provisions and Funding: The German Experience",International Yearbook of Soil Law and Policy 2022, vol. 2022, Cham: Springer International Publishing, pp. 83–106,doi:10.1007/978-3-031-40609-6_4,ISBN978-3-031-40608-9
^Ferber, Uwe (2011)."Circular flow land use management".International Conference Virtual City and Territory (7è: 2011: Lisboa). Coimbra: Department of Civil Engineering of the University of Coimbra and e-GEO, Research Center in Geography and Regional Planning of the Faculty of Social Sciences and Humanities of the Nova University of Lisbon. pp. 775–778.doi:10.5821/ctv.7829.
