Urban futures: the sustainable management of the ground beneath cities

Over half of the world's population now live in cities. In 2011 it was estimated that the global population exceeded 7 billion. Pressures on the environment including land use are increasing. The ground beneath cities and the interaction between physical, biological and chemical processes provides natural capital on which society depends. These benefits and the ground properties and processes that support and deliver them can be considered ecosystem services. Characterizing the ground properties on which ecosystem services depend involves a qualitative assessment of positive and negative impacts of proposed urban sustainability solutions, including use of the ground. The sustainability of a proposed solution depends on how the future might unfold. Future scenario analysis allows consideration of the social, technological, economic, environmental and political changes that may determine the ability of a proposed solution to deliver its benefits now and in the future. Analysis of the positive and negative impacts of a proposed use of the ground on ecosystem function, measured against future scenarios of change, can be integrated to deliver strategies for the future management of the ground and the wider environment beneath cities.