This document discusses the rationale for maintaining and enhancing the Green Belt around cities in the UK. It argues that natural capital, like the open spaces and woodlands provided by the Green Belt, needs to be located near population centers to provide multiple benefits. These benefits include improved air quality, health outcomes from access to leisure activities, and biodiversity protection. While some argue the Green Belt inhibits housing and economic growth, the document counters that brownfield sites and increased density can address housing needs, and that truly sustainable and resilient economic growth depends on maintaining natural capital. It concludes by envisioning how an enhanced Green Belt could better integrate access to green spaces and natural capital into urban living for current and future generations.