Buildings are responsible for significant impacts on the environment. They account for around half the UK's emissions of carbon dioxide, the main 'greenhouse' gas. However the environmental impact of a building is not restricted to energy use. The Building Research Establishment's Environmental Assessment Method (BREEAM) is a tool that measures the overall environmental impact of a building throughout its life and provides guidance on ways of minimising the adverse effects on the global and local environment, whilst promoting a healthy and comfortable indoor environment. The assessments generate a single score, which allows buildings to be directly comparable with others within a sector. The methodology is flexible, technically robust and independently governed. As a result, BREEAM is a widely accepted and respected scheme that sets a benchmark for sustainable development in the built environment worldwide.