The artificialization of soil, an environment, or natural or semi-natural habitat is the loss of its qualities: its naturalness, a quality that includes a self-sustaining capacity to harbor certain biodiversity, natural cycles (carbon, nitrogen, water, oxygen cycles, etc.), and biogeochemical qualities (carbon sink, for example). It is generally accompanied by a loss of self-healing capacity on the part of the environment (reduced ecological resilience).
Artificialization is often summed up as the disappearance of natural spaces under concrete or bitumen, during the construction of buildings (apartment blocks, hotels, houses, shops, industries, parking lots) or transport networks. While soil sealing is a huge part of land artificialisation, more generally, it takes place when natural environments are heavily transformed by man. For example, leisure and sports facilities (green spaces, golf courses, sports fields, motocross courses, winter sports resorts, etc.), canals, road embankments, and artificial lighting can each lead to ecological traps and other impacts, animal mortality on roads, light pollution, etc., and can also lead to the creation of new habitats. It could also be mentioned the areas developed for military purposes (military testing grounds, underground tunnels, fortifications, glacis, no-man's-land, etc.).
In Europe in 2015, the surface area of sealed land exceeded one million square kilometers, i.e. 2.3% of the European Union's surface area and 200 m² per inhabitant (over 50,000 km2 and 9.4% of the territory in France). On average, 165 ha, or 1,650,000 m² of natural environments and farmland, are destroyed every day in France and replaced by roads, housing, and business parks, as part of the urban sprawl phenomenon. Between 2005 and 2015, this represented almost 6,000 km², the size of a département in ten years. One of the aims of the French Green and Blue Network (TVB or Schéma régional de cohérence écologique) is to limit this phenomenon and mitigate its consequences. Since 2018, the goal of Zero Net Artificialization has been a major roadmap in the fight against artificialization.
Examples of artificialization
Areas affected by artificialization include:
Rural areas and agricultural zones (especially when exposed to intensive, industrial agriculture). This also applies to grasslands which, when enriched with nutrients or sown with plowing, no longer harbor much of the biodiversity of a natural grassland; Certain forest or silvicultural environments where monocultures are practiced (poplar plantations, rubber, eucalyptus, oil palm, short rotation coppice (SRC) or willow, etc., or forests planted or managed largely on the principle of artificial regeneration and heavily fragmented by roads, tracks, and paths); Watercourses canalized and fragmented by large dams, cultivated wetlands (e.g. rice paddies), drained wetlands or wetland basins, polders, etc.; Coastlines and their estuaries, increasingly developed for tourism, industry, and transport: discharge into the sea, construction of dykes, channels, ports, underwater quarries, etc.
Extent and progression of the phenomenon
As far as geomorphological and subsoil effects are concerned, the artificialization of the environment began modestly in prehistoric times: clearing by fire, occupation, and development of caves, increasingly sedentary and built-up human habitat, digging of shafts in the subsoil for flint mining, then seed silos and shafts or galleries for the exploitation of metal ore seams, from the Bronze Age onwards.
This was followed by larger-scale developments, often designed for the intensive exploitation of water from the great rivers (Nile, Tigris, Euphrates...). In Europe, beaver dams (and the beavers themselves, hunted for their meat and fur), which maintained water reserves and open riparian habitats, were destroyed. At the same time, the construction of fords, then bridges, dykes, mills, and systems for impounding and regulating watercourses and for drainage spread, culminating in major episodes of polderization, etc. At the same time, the urbanization of the region increased. At the same time, urbanization expanded, supported by networks of roads and trading centers (e.g. the Silk Road). Peri-urban waste dumps appeared, gradually buried beneath the urban sprawl. Cemeteries, monuments, and fortifications (e.g. the Great Wall of China) are accompanied by vast clearing, leveling, and earthworks (terraces, embankments, sunken paths, low walls).
During the Anthropocene, the development of coal mines, the oil industry, railroads, automobiles, and tractors led to more intensive farming. This accelerated the anthropization of the landscape and subsoil, colonized by millions of kilometers of cables, pipes, and sewers, including in the colonies of wealthy countries on every continent. The network of roads, freeways, and railroads is expanding, as are industrial, commercial, sports, and sometimes military facilities. At the end of the twentieth century, the pace of artificialization accelerated even further and is visible on satellite imagery.
Some areas are particularly hard hit: a large part of the coastline and estuaries of many countries has been artificialized by the construction of seaside resorts, coastal road networks, and port facilities. Cities and their outskirts, as well as all agricultural environments, and all ancient forests in temperate countries and then in most tropical countries (with the exception of a few protected massifs).
Artificialization is moving towards developing countries, with peri-urbanization particularly marked in the vicinity of megacities and urban metropolises (in France, for example, the Île-de-France and Toulouse). In wealthy countries, it's often linked to the success of the single-family home, which is also reflected in urban sprawl and peri-urbanization.
In France
The French urban planning code defines artificialisation as "the lasting alteration of all or part of a soil's ecological functions, in particular its biological, hydric and climatic functions, as well as its agronomic potential by its occupation or use".
In 2006, 8.3% of mainland France was affected by land artificialisation, a figure that rose to 9.4% in 2015. In fifty years, seven million hectares of land have been buried for housing (40%), the economy (30%: businesses, warehouses, shops), and transport infrastructure (30%). Since 2009, 90% of land artificialisation has been at the expense of fertile soils.
According to Corine Land Cover statistics on land use in France, the French region with the least amount of artificial land is Corsica, with 2.1% of its surface area, while Île-de-France tops the list with 21.6%.
Artificialization is highly polarized at the national level. A study by the Cerema (the French Environment and Spatial Planning Agency) reveals a high level of artificialisation on the coast and around medium-sized towns and cities. In July 2019, annual data on a municipal scale for the period 2009-2017 were published, and have been updated annually since. In 2015 and 2016, it was estimated that the phenomenon had "stabilized" (at 9.3% of mainland France) thanks to the 2008 crisis, which slowed land artificialisation (to +0.8% per year). Recent data, however, confirm a resumption of the phenomenon since 2016: after a period of decline between 2011 and 2016, artificialisation is again increasing its pace, reaching 23,454 ha between 2016 and 2017. In 2022, the Cerema dashboard reveals that 21,079 ha have been taken or pre-empted in 2021 in France on natural and agricultural spaces, almost 1,200 ha more than in 2020, but almost 1,300 ha less than in 2019. Despite this upturn, the Senate majority is calling for a moratorium on the application of the 2021 Climate and Resilience Act, tabling bills to extend deadlines and pointing to the lack of financial resources dedicated to achieving the goal of zero net artificialization. In June 2022, the Association des maires de France (AMF) lodged an appeal with the Conseil d'État against two decrees implementing this law. Christophe Béchu, Minister of Ecological Transition and Territorial Cohesion, has said he is open to rewriting some of the decrees.
In 2009, according to the Institut français de l'environnement (IFEN), land artificialisation increased by 60,000 ha per year (or 6,000 km2 in ten years, equivalent to the size of the Seine-et-Marne département). The 885 coastal municipalities are particularly hard hit. Despite the "natural" and rural areas spared thanks to the Conservatoire du littoral and the Littoral law, less than 500 m from the sea, the rate of artificialization (28.2% of the territory artificialized on average) is 5.5 times higher than the average for metropolitan France. The coastlines of Nord-Pas-de-Calais, Pays de la Loire, Languedoc-Roussillon, and PACA are the most artificialized by construction, while those of Normandy, Brittany and Poitou-Charentes are artificialized by agriculture. Coastal forests and semi-natural areas dominate the landscape only in Aquitaine (with the Atlantic coastal dune forest) and Corsica; Despite the risk of marine invasions induced by rising oceans, this artificialization of the coast is steadily increasing:
From 2000 to 2006, almost 10,000 ha were artificialized on the 10 km strip of coastline alone in mainland France; From 2000 to 2006, development was highest in the 500 to 2,000 m seaward strip (on 0.42% of the territory), i.e. 2.8 times the average for mainland France; On the Channel-North Sea coast, artificial development is more evenly distributed from the coastline to two kilometers inland, before decreasing; In the Atlantic, on the other hand, artificial development has slowed down along the coastline, increasing between 500 and 1,000 m, before gradually decreasing inland; On the Mediterranean coast, from 2000 to 2006, artificial development was almost uniform from the coastline to 10 km from the sea.
In China According to Jean-François Doulet,Jean-François Doulet is a geographer and deputy director of the Franco-Chinese Centre for Cities and Territories. in the 2010s, the urbanized surface area in China almost quadrupled from the early 1980s to 2012. Artificialization was estimated in 2012 to be equivalent to twice the surface area of the Île-de-France region each year, and a 15-year estimate is for a surface area equivalent to the current urbanized area of Europe.
Causes Urbanization leads to the creation of suburban areas, housing estates, and towns. Support for commercial activity and tax competition between communes and agglomerations to attract companies leads to the construction of business parks (commercial zones, industrial zones, etc.) and huge parking lots to park their users; The growing mobility of the population has led to the construction and expansion of transport networks.
Consequences
Impact on climate In terms of global warming, artificial surfaces, usually dark in color, affect albedo by absorbing solar radiation and emitting long-wave infrared radiation. This radiation is reflected to Earth by greenhouse gases in the atmosphere, contributing to global warming.
This artificialization may have an impact on the local climate, by increasing surface temperatures (LST), as shown by the satellite image of surface temperature measurement opposite.
According to the IPCC's Sixth Assessment Report, reducing vegetation affects the local and adjacent climate through the subsequent disruption of the water cycle). Climate balances are complex and closely linked to the properties of physical surfaces, which also have biological functions. In particular, living organisms have developed strategies for capturing and storing water. Examples include the role of Pseudomonas syringae as a nucleating agent, the effect of earthworm galleries on water infiltration in soils, or the effect of glomalin production by fungi on soil compaction.