Imperviousness means the covering of the soil surface with impermeable materials because of urban development and infrastructure construction. Imperviousness negatively affects biodiversity, carbon storage and sequestration, soil hydrological properties, ecosystem services and nature conservation. In 2018, sealing affected 97,744 km2 (2.23%) of EU plus United Kingdom territories. Almost half the area of cities is sealed and about 4% of the EU's coastal regions and floodplains are impermeable, jeopardising adaptation to heatwaves and floods and decreasing carbon sequestration.

Figure 1. Imperviousness in MAES ecosystems — floodplains, coastal zones and protected areas — 2018

The continuing rapid expansion of sealed surfaces — often improperly planned and unjustified by the population's needs — leads to hydrological impacts, which influence run-off in urban catchments, and the loss of crop production, which affect the global carbon cycle. Sealing is also a key driver of the loss of biodiversity and ecosystem services. The European Commission’s roadmap to a resource efficient Europe introduced a ‘no net land take by 2050’ initiative that aims to ensure that either all new urbanisation occurs on brownfields or any new land take is compensated for by reclaiming artificial land. Land take and sealing are also relevant to several targets of the EU biodiversity strategy for 2030, aimed at protecting and restoring nature . As sealing hampers nature’s ability to deliver a wide range of environmental, climate change adaptation and biodiversity benefits, it also affects the implementation of the EU strategy on green infrastructure and the long-term objectives of the common agricultural policy (CAP) — viable food production, the sustainable management of natural resources, climate action and balanced territorial development .

In 2018, 97,903 km2 of soil was sealed in the 27 Member States plus the United Kingdom (EU-27 + UK), amounting to 522 inhabitants per km2. Cities and towns are most affected by sealing (42% and 30% sealed, respectively), contributing to the development of urban heat islands, floods and impacts on human health. Croplands sealing amounted to almost 14%, which is important given their role in Europe’s food and fibre production. Grassland ecosystems — highly important for biodiversity and ecosystem services — were sealed on average in 3% of the EU, whereas approximately 2% of forests — important sources of food, fibre, habitats and important carbon sinks — were sealed.

Coastal areas are increasingly exposed to climate change and urbanisation. In the EU-27 + UK region, 16,000 km2 (4%) of coastal zones were sealed in 2018, jeopardising their role in carbon sequestration, climate change adaptation and coastal ecosystem protection. Floodplains are also important for climate change adaptation, acting as buffers during flooding events. Despite this, 3% (11,367 km2) of floodplains were sealed in the EU-27 + UK region in 2018. Even protected areas are not free from sealing, with 0.6% of all protected areas (7,013 km2) affected.

Figure 2. Imperviousness in MAES ecosystems by country, 2018

In 2018, ecosystems in Malta (19% sealed), the Netherlands and Belgium (both 8% sealed) were the most impervious (link to dashboard). When not considering urban ecosystems, croplands were the most sealed ecosystems in these countries together with Denmark and Italy.

Sealing in forests was minimal in 2018, affecting less than 500 km2 (1%) of forests in each country. However, pasture and grasslands, important for carbon sequestration and biodiversity, were more affected, with over 1,700 km2 of these land types being sealed in Germany and almost 900 km2 in France and the United Kingdom. Belgium’s grasslands were most affected by sealing in relative terms, with 4% affected, followed by Germany, the Netherlands and Luxembourg (3-3.4%). In Switzerland, 4.4% of floodplains were sealed, more than  in Belgium, Luxembourg and the Netherlands (3%). Thirty per cent of Malta’s coastal region, mostly wetlands, was sealed, as were over 15% of the Belgian and Slovenian coastlines.