This indicator measures the covering of the soil surface with non-permeable materials, hence indicating imperviousness. The aggregation of imperviousness values to reference units, such as urban areas, floodplains, coastal zones or protected areas is performed using the integrated spatial data platform of the EEA.
Methodology for indicator calculation
• The 100-m imperviousness product of 2018, aggregated from the 10-m 2018 imperviousness data set for analytical performance, is the basis for this indicator.
• The calculation used to obtain the data presented in the indicator is performed by ingesting the 100-m imperviousness data set into the EEA’s integrated data platform to create harmonised results with other indicators based on spatial data sets and using a similar methodology.
• The data cube approach used for the data platform enables the extraction of statistics based on a system of grid cells with a side length of 100 m (an area of 100 ha).
• Statistics are calculated in the data cube as regional aggregates, such as NUTS-0 to NUTS-3, land cover classes, protected areas, floodplains and coastal zones.
• All data sets used for the aggregation are registered in the EEA’s Spatial Data Infrastructure (SDI) under the reference layers node of the integrated data platform:
The main policy-relevant objective of this indicator is to measure the extent and dynamics (change) of soil sealing, resulting from the development of urban and other artificial land.
At the United Nations Conference on Sustainable Development held in Rio in 2012 (Rio+20), world leaders identified land and soil degradation as a global problem and committed to ‘strive to achieve a land degradation-neutral world in the context of sustainable development’. At the EU level, the Seventh Environment Action Programme (7th EAP) includes a strong focus on the unsustainable use of land and soil, including the issue of soil sealing explicitly (EU, 2013a). In this context, the 7th EAP refers to the Commission Staff Working Document ‘Guidelines on best practice to limit, mitigate or compensate soil sealing’ .
In addition, land take is explicitly mentioned in Chapter 23 of the 7th EAP:
‘Every year more than 1,000 km² of land are taken for housing, industry, transport or recreational purposes. Such long-term changes are difficult or costly to reverse, and nearly always involve trade-offs between various social, economic and environmental needs. Environmental considerations including water protection and biodiversity conservation should be integrated into planning decisions relating to land use so that they are made more sustainable, with a view to making progress towards the objective of 'no net land take', by 2050’ .
In recognition of the importance of land in safeguarding natural resources, the Commission is considering publishing a communication on ‘land as a resource’.
Other important references can be found in the Communication from the Commission ‘A sustainable Europe for a better world: a European Union strategy for sustainable development’ and the thematic documents related to it , as well as the concept of territorial cohesion.
Targets
Although there are no quantitative targets for soil sealing/imperviousness at EU level, different documents reflect the need for better planning to control urban growth and the extension of infrastructure. Policies relating explicitly to land use issues, and especially physical and spatial planning, have, until now, generally been the responsibility of authorities in individual Member States. The European Commission’s roadmap to a resource efficient Europe (EC, 2011) introduced, for the first time, 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.
EU policy, although not establishing requirements for spatial planning directly, provides a framework for planning. At the EU level, the 1999 European Spatial Development Perspective (ESDP) , a non-binding framework that aims to coordinate various European regional policy impacts, advocates the development of a sustainable, polycentric and balanced urban system with compact cities and the strengthening of partnerships between urban and rural areas, as well as parity of access to infrastructure and knowledge, and evidence-based management of natural areas and cultural heritage. The 2008 Green Paper on territorial cohesion and the 2007 EU territorial agenda and action plan by the Territorial Agenda of the EU and the action programme for its implementation (COPTA, 2007) build further on the ESDP. Specific, relevant actions in the field of land in particular are Action 2.1d ‘Urban sprawl’ and Action 2.2 ‘Territorial impact of EU policies’.
Demand for new urban areas may be partly satisfied by brownfield remediation. The environmental advantages of this are clear: relieving pressure on rural areas and greenfield sites, reducing pollution costs, enabling more efficient energy use and natural resource consumption, and facilitating economic diversification and emerging habitat (housing) requirements. There are several examples of European regional strategies for economic regeneration and brownfield development (The OECD Territorial Outlook 2001). On average, land recycling increased steadily between 1990 and 2012 on an annual basis, with considerable variation between and within countries. Stronger links between EU urban and soil policies could encourage this further (e.g. following up relevant 6th EAP thematic strategies).
Methodology uncertainty
The methodology for deriving the indicator is simple and introduces very little uncertainty. However, it needs to be fully understood that the yearly averages are valid for only the 3-year reference period under consideration. Possible variation within the 3-year period (for individual years) is currently not captured.
Data sets uncertainty
This indicator is based directly on the mapping of soil sealing/imperviousness using Earth observation data at about 10-m spatial resolution. Real sealing will differ from the values derived in this way for various reasons:
• The spatial resolution of the input imagery means that very small sealed surfaces will sometimes not be captured, e.g. small buildings and small paved roads, and other sealed surfaces with a very small footprint. This can lead to an underestimation of sealing.
• As with all Earth observation-derived products, the data contain omission errors (sealed surfaces not detected) and commission errors (areas wrongly classified as sealed). The distribution of these errors depends on the quality of the input data, calibration during production and local differences in spectral contrast (which makes sealing in some locations ‘easier’ to detect than in other locations, depending on the context).
Rationale uncertainty
No uncertainty has been identified.
