Land is consumed when soil is covered by buildings or is otherwise rendered impervious. This disrupts vital soil functions and permanently damages the natural ecosystem’s ability to thrive. Soils have a large variety of functions which need to be protected: they provide habitats for plants and animals, they store and filter the groundwater, they act as buffers against pollutants, they are the foundation for agriculture and for healthy living, and they are an archive of natural and cultural history (Section 2 BBodSchG). These fundamental functions of the soil must be secured by adequately taking the needs of soil protection into account when planning for the future.
Soil is increasingly gaining importance in societal and ecopolitical matters, especially in view of its adaptation triggered by climate change, the carbon and water storage capacity of the soil and biodiversity. This has led to the introduction of measures and regulations at national level to reduce new land consumption and impervious soil coverage as well as a need for sustainable land management in cities and municipalities.
‘The settlement and transport area in Germany expanded by an average of 52 hectares per day during the four-year period from 2019 to 2022. The daily expansion was therefore lower compared to the previous period’s indicator value (55 hectares per day in 2018 to 2021)’. (Destatis, 2024a, 2024b, 2024c; see also UBA, 2024). At both the international and national levels, ambitious targets and measures are being implemented to curb new land consumption. The United Nations’ global Sustainable Development Goal 15 and the German Sustainable Development Strategy, which builds on it, emphasise the need to protect and sustainably manage land as a resource. Both frameworks share a key objective: land degradation neutrality (UN, 2015; Federal Government, 2021).
With the German Sustainable Development Strategy 2016, the Federal Government set the 2020 goal of 30 hectares to ‘under 30 hectares per day’ by the year 2030 (Federal Government, 2017; Destasis, 2018). In the updated Federal Government’s Sustainable Development Strategy 2021, the aim is to establish a closed-loop land-use regime by 2050, meaning that, in net terms, no additional land shall be developed for the purposes of settlement or transport (Federal Government, 2021).
The difference between new land consumption and impervious soil coverage
The term ‘new land consumption’ refers to the net increase in settlement and traffic areas. The indicator ‘increase in settlement and transport area’ applies to regions previously used for agriculture and forestry that have been converted into settlement or transport areas. It may therefore also include pervious spaces, such as urban parks, courtyards, greenery along roads, cemeteries, and allotment gardens. Particularly in urban areas this indicator is often not enough to determine the actual condition of the soil and assess the sustainable management of this resource. The impervious area of a city may increase even if land consumption remains the same, such as through inner development and structural redensification. Therefore, information on the degree of impervious soil coverage and its development generally provides more detailed insights into the consumption of land as a natural resource in the urban area (LABO, 2020).
Impervious soil coverage (‘sealing’) is one of the 16 core indicators by which sustainable development in the State of Berlin is measured (AfS Berlin-Brandenburg, 2021). Based on statutory regulations, this indicator helps ensure that soil, an increasingly limited resource, is considered in the complex interplay of construction and planning processes, while also strengthening efforts to protect and restore its valuable functions.
The goal of the Senate Department for Urban Mobility, Transport, Climate Action and the Environment and the Senate Department for Urban Development, Building and Housing is therefore to provide instruments for an active, practice-oriented land management system. These make it easier, in particular, for the soil protection authorities to perform their tasks as public authorities, e.g. in the context of urban development planning, and of competently integrating aspects of soil-protection in the environmental impact assessment process.
One problem that appears regularly in planning practice is that the impervious covers required for developing an area can hardly be offset in material terms. In principle, the best compensation would involve the removal of the impervious cover (de-sealing) of another area. However, due to the restrictions of availability of most land for such measures, it is difficult to find areas in Berlin where the impervious cover may actually be removed. It is then not possible, using the Environmental Impact Assessment, to implement such measures, due to the lack of any adequate available land. Proposals for the removal of impervious coverage usually have a chance to be realised if areas with the potential of having their impervious cover removed are already known, have been checked for suitability, and are listed in the register.
An initial step was the compilation of Environmental Atlas Map ‘Planning Advice for Soil Protection’, an important planning instrument for soil protection assessment. The weighing of the various functions and sensitivities of the Berlin soils permitted a differentiated evaluation of urban development planning. For example, in the case of soils which, from a soil protection viewpoint, were classed as particularly valuable, the search for alternative sites for relevant development planning projects was recommended (see also SenStadt, 2020).
The project ‘Potential for the Removal of Impervious Coverage in Berlin’ (only available in German) was initiated to improve the availability of areas for impervious coverage removal as a second step. The goal of the project is to identify and evaluate land which could potentially have its impervious cover permanently removed in the foreseeable future. To the extent possible, the efficacy of the soil is to be restored, and habitats valuable from a conservationist point of view are to be developed for plants and animals. In addition, the aim is to support a geographical decoupling of the sites of impairment and those of restoration by means of a city-wide survey and a uniform system for the evaluation of the recorded areas. In individual cases, the instrument of impact mitigation regulation (according to construction law and conservation law) may be considered an option here. The recorded areas generally represent available land that may be used to offset human intervention in the soil or the permanent loss of soil functions. They also indicate land suitable for impervious coverage removal measures within the framework of funding measures.
Since 2010, as part of several project phases, research has been conducted across all Berlin boroughs, in the four Berlin forestry agencies, the Senate Departments for Urban Development, Building and Housing (SenStadt) and Education, Youth and Family (SenBJF) as well as among private owners. The most recent update was carried out between January 2024 and November 2024. The data obtained during the research process was compiled in a database. Within the ongoing Berlin programme focused on removing impervious soil covers, the next goal is to consolidate existing records of potential areas suitable for this purpose. One approach is to explore participatory opportunities to identify previously overlooked areas for the removal of impervious covers, with input from various stakeholders across the city.
In order to support the implementation of removal measures, a tool to derive simplified cost approaches for the expected dismantling costs has been prepared (including an Excel input file to simplify cost estimates of removal measures). Furthermore, the tool is available online to assist in the restoration of soil functions following the process of removing impervious covers. Additionally, regular newsletters provide updates on current events concerning the removal of impervious soil covers. In 2021, the documentation of a removal project was published, outlining the project process, financing and the parties involved. Another report on a current project is scheduled for publication in 2025, documenting the removal measures undertaken at the former Marienfelde borough nursery. Please refer to ‘Entsiegelungspotenziale in Berlin – Berlin.de’ for the newsletter, the documentation and the tools mentioned (only available in German).