Drivers of the Business Case The Business Case Strengthening the Case: Social Value The Social Value Case Future-Proofing The Value Proposition Natural Capital Natural capital can be defined as the world’s stocks of natural assets which include geology, soil, air, water and biodiversity 117 . The continued, thriving existence of these natural resources are essential to supporting the ecosystem services that our survival on this planet, in both our urban and rural environments, ultimately depend on. Natural resources and ecosystem services support many key economic activities, from farming, to energy generation, and material extraction for medicines or building materials 118 . With a particular focus on the built environment, nature also provides physical protection to numerous key human settlements, and is essential for climate regulation and the continued cycling of water, materials and chemicals, essential to our continued utilisation of the planet for human habitation. These benefits translate to better air quality, lower urban heat island effect, stronger nutrient cycle and also enhanced resilience to climate change impacts. However — the over-extraction of natural capital, without allowing adequate recovery of natural systems, poses a significant risk of local, regional or even global ecosystem collapse 119 . Natural capital is able to be financially quantified — and is valued at USD $145 trillion/ year, twice as much as global aggregate GDP 120 . Many studies have quantified the value provided by nature in the built environment in economic terms — for example, street trees in California provide USD $ 1 billion per year in ecosystem services, through climatic regulation and flood prevention in urban environments, and Mexico’s mangrove forests provide an annual USD $ 70 billion to the economy through storm protection and protecting the fishing industry 121 . Therefore, natural capital should be considered part of the business case for a sustainable built environment. Protecting ecosystems and biodiversity today can protect against future replenishment costs down the line, and also provide a range of benefits. In the real estate sector, there is opportunity to enhance natural capital by supporting the continued availability of resources used for building construction and operation, such as: • Timber, by increasing demand for sustainable materials, favouring re-use as far as possible • Water, by promoting water efficiency at all stages of lifecycle and tracking and reporting during construction and operation phases • Biodiversity, by actively increasing diversity of flora and fauna on-site and in local communities, and supporting ecosystem development for pollinators and other key species. The protection of nature is also, undeniably, the right thing to do — but in a world of competing priorities it can be difficult to balance the environmental and the economic. Natural capital enables us to place a financial value on the invaluable natural services provided by our planet, with which we can hope the clarity of the business case will inspire preservation and regeneration of our natural ecosystems. A WORLD GREEN BUILDING COUNCIL REPORT | 41