Geosystem services: A concept in support of sustainable development of the subsurface C.C.D.F. Van Ree a,b,n , P.J.H. van Beukering a a VU University, Institute for Environmental Studies, De Boelelaan 1087,1081 HV Amsterdam, The Netherlands b Deltares, Unit Geo-engineering, P.O. Box 177, 2600 MH Delft, The Netherlands article info Article history: Received 11 March 2016 Received in revised form 8 June 2016 Accepted 14 June 2016 Keywords: Geosystem services Ecosystem services Subsurface Environmental economics Sustainability Urbanization abstract Because functions of the subsurface are hidden from view, its important role in society is often taken for granted. Underground use in cities and subsurface resource extraction rapidly increase. Ensuring sus- tainability of the subsurface role requires balancing between exploitation and conservation, recognizing the non-renewability of abiotic resources and the long time cycles in the subsurface. This paper introduces the concept of geosystem services as a framework to analyze the issue of sustainable use of the subsurface in a systemic and holistic manner. Four main elements make up the framework: geosystems, services, values, and governance. Complementarity between the concepts of geosystem and ecosystems services is highlighted by classifying geosystem services in provisioning, regulating, cultural and supporting services. Geosystem services are distinguished from ecosystem ser- vices by systematically reflecting on three cross-cutting themes (i.e. space, scale and time). Applying the concept of ‘geosystem services’ results in improved integration in areas where trade-offs occur between ‘geosystem services’ stemming from the subsurface and ‘ecosystem services’ at surface. The geosystem services concept helps framing a more sustainable process of urbanization, and contributes to a spatially explicit linkage of (mineral) resource production to consumption, environmental impacts on the eco- system and (global) governance of resources and resource efficiencies. & 2016 Elsevier B.V. All rights reserved. 1. Introduction When thinking about their surroundings humans are particularly aware of the visible environment, such as landscape, air and water. The subsurface is mostly seen as a dark, useless and even threatening place. However, the subsurface is much more important than most people are aware of in providing key functions and services to fulfill the needs of societies. With the world population growing to 9.7 billion people, the urbanization rate rising to 66%, and global economy to triple in size in 2050 (United Nations Population Divi- sion, 2014, 2015; OECD, 2014), the impact and dependency on the subsurface is likely to increase significantly in the coming decades (Crutzen and Stoermer, 2000; Andrews-Speed et al., 2012). The subsurface 1 is defined as the zone below the earth's surface, both in subterranean as well as submarine areas. On the one hand, we distinguish ecological systems, e.g. biomes at surface in the terrestrial environment and marine ecosystems, which are related to biotic communities and activity influenced by for ex- ample the availability of light, water and oxygen. The lithosphere and its geosystems, on the other hand, are associated with low biological activity due to the lack of light and often anaerobic conditions. The geosystem can be characterised by specific geo- logical sequences, structures, landscapes and the rocks, minerals and fossils that are present. Additional distinctive features used in characterising geosystems relate to geophysical and geochemical drivers of change such as the risk of specific natural hazards (e.g. earth quakes, landslides, liquefaction, and subsidence) as well as specific anthropogenic pressures (e.g. subsurface construction, mineral extraction, contamination). Sustainable development of the subsurface requires the fram- ing of (mainly) abiotic resources (including 3D-space) and their importance for human well-being (e.g. Kennedy et al., 2015; Zhang et al., 2013). To date, authoritative assessments on the role of the subsurface and the related environmental trade-offs are missing. The main reason for this lacuna is the lack of a comprehensive and integrative framework to address the subsurface and its con- tributions to human welfare (De Mulder et al., 2012). We express Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/ecoser Ecosystem Services http://dx.doi.org/10.1016/j.ecoser.2016.06.004 2212-0416/& 2016 Elsevier B.V. All rights reserved. n Corresponding author at: Deltares, Unit Geo-engineering, P.O. Box 177, 2600 MH Delft, The Netherlands. E-mail address: Derk.vanRee@deltares.nl (C.C.D.F. Van Ree). 1 In theory the ‘ subsurface’ includes everything between the Earths’ surface and the very center of the planet, 6370 km below our feet. However, humans have never pene- trated much deeper than 12 km and it is not likely that a signi ficant number of activities will go beyond that depth over the next few decades. Oil and gas recovery are generally amongst the deeper extractions and are withdrawn from depths between 2 and 3 km on average (EIA, 2015). The deeper open cast mines reached 900 m of depth. The depth to which urban infrastructure (networks, buildings, tunnels) is constructed is generally much less and ranges from meters to tens of meters on average (De Mulder et al., 2012). Ecosystem Services 20 (2016) 30–36