Land cover accounts — an approach to geospatial environmental accounting

Policy relevance of land accounting

Land is a resource that supports important production functions and ecosystem services, such as the provision of food and fibre, the maintenance of nutrient cycling, terrestrial biodiversity, water regulation and purification, and climate change mitigation (EEA, 2019a). The integration of land cover, land use and land use change data with other thematic areas is required to address the climate and environmental sustainability priorities of the European Green Deal and other EU policies.

At a global level, land degradation neutrality is included in target 15.3 of the United Nations (UN) Sustainable Development Goals for 2030 (SDGs) and land use information underpins several other targets, e.g. SDG target 11.3 on sustainable cities and SDG target 15.1 on conservation, restoration and sustainable use of ecosystems. Moreover, SDG target 15.9 addresses the integration of ecosystem and biodiversity values into accounting, among other things. More recently, the  European Strategy for Environmental Accounts 2019-2023 describes priorities and actions for the use of environmental accounts in a harmonised way.

The EEA’s approach to environmental accounting uses geospatial data and respects the international standards for measuring the environment and its relationship with the economy, as set out in the UN System of Environmental Economic Accounting — Central Framework. A separate briefing describes EEA’s approach to developing ecosystem extent and condition accounts (EEA, 2020).

Data and methods for land accounts

Accounting is an economic term referring to the systematic process of communicating financial gains and losses (i.e. credit and debit). Land accounting therefore requires uniform and harmonised data on gains and losses in different land categories across the territorial extent in question. Such data come from the monitoring of land cover as seen from Earth observation instruments, such as satellites. Replacing economic assets in the accounts by land cover stocks means the shares of different land cover within spatial reporting units, and changes within them, can be quantified. Land cover changes can therefore be associated with socio-economic land use processes, and analysis of these changes enables us to evaluate pressures from land use change on the environment.

The EEA’s land accounting is based on the Copernicus CORINE Land Cover (CLC) datasets for the years 2000, 2006, 2012 and 2018. CLC status layers for a given reference year (e.g. 2018) use mapping units of 25 hectares (ha), but CLC change datasets (e.g. from 2012 to 2018) capture changes at 5 ha. Therefore, simply subtracting one data set from another does not produce the CLC change dataset. In order to solve this, land cover accounting layers are created to produce a harmonised time series for the whole period 2000-2018 (ETC/ULS 2020).

The CLC data set has 44 classes and the number of potential unique land cover changes between two observation periods is large (i.e. 44*43 = 1 892). Grouping them into change categories known as Land Cover Flows (LCFs) provides transparent assessments, since the flow statistics between individual CLC classes or groupings give important insights into the nature of land cover change processes. LCFs are defined using three hierarchies that describe different land cover or land use change processes. Of these, level 1 is the most aggregated, containing nine LCF types (EEA, 2006).

The EEA’s Integrated Data Platform (ETC/ULS, 2020) is made up of geospatial data architecture and IT system infrastructure to enable the consistent and systematic production of land and ecosystem accounts. In detail, the Spatial Data Infrastructure organises and catalogues geospatial data with an interactive interface. The thematic node Environmental Accounting Reference Layers (EARL) assembles harmonised and quality assured datasets. Interactive dashboards enable the exploration of geospatial datasets that describe our natural capital.

The IT infrastructure of the IDP contains the Joint Environmental Data Infrastructure (JEDI, ETC/ULS, 2020), which uses cloud infrastructure to transfer geospatial data into tabular formats (dimensions). Using data cubes, the dimensions of land cover datasets may be integrated with other dimensions, such as administrative boundaries, biogeographical regions or bio-physical and socio-economic data. For the integration, uniform reference grids are used with 1 km x 1 km and 100 m x 100 m cells as the accounting units, following INSPIRE directive specifications.

A data cube allows for user driven queries and gives tabular, chart or map results. The EEA’s own interactive dashboard for land accounts (EEA 2019c) displays the land stock and changes to it, detailing statistics by year and by geographical unit (Box 1). Moreover, the data cube allows for the efficient combination of various categories of a dimension (e.g. arable lands and permanent crops) or combinations of dimensions aggregated in grids or administrative boundaries.

Accounting for major land use processes: example on land take and sealing

Figure 1. Land converted to urban areas in the EEA-39, 2000-2018

Source: EEA

Land take occurs when urban areas and sealed surfaces expand at the cost of more natural land cover types (EEA, 2019a), reducing the potential of the land to perform various functions and crucial ecosystem services (EEA, 2019b). The major factors behind land take in the EEA-39 region are industrial and commercial activities, and residential sprawl (EEA, 2019a)  concentrated around larger urban agglomerations (Figure 1). In the EEA-39 in the period 2000-2018, 14 049 km² was urbanised as indicated by the land take interactive dashboard, mostly at the expense of arable lands and permanent crops (around 50 % of the total urbanisation), and of pastures and mosaic farmlands (almost 30 %). Soil sealing — an extreme form of land take — covers lands with impermeable surfaces, resulting in a decline in land functions. Both land take and soil sealing have slowed down, although sealing less so: 1.7 % more of the land area was sealed in the period 2012-2015 (compared with an increase of 2.4 % in sealing between 2006 and 2009 in the EEA-39 region (see the soil sealing dashboard).

Land recycling — the reuse of abandoned, vacant or underused land for redevelopment (EEA, 2018) — is still low in all European countries: on average, land recycling accounted for only 13.5 % of total land consumption in European cities in the period 2006-2012 (see land recycling dashboard). The largest component of land recycling is densification^[1], i.e. when new urban development makes maximum use of urban space and existing infrastructure.

Accounting for major land use types: example on agriculture and forestry

Figure 2. Arable land and permanent crop land cover change, 2000-2018

Source: EEA