Climate change is one of the greatest environmental challenges of our time. Global warming due to anthropogenic or ‘human-generated’ greenhouse gas (GHG) emissions to the atmosphere, referred to as carbon emissions (see 2.1), may have severe adverse environmental, social and financial effects around the world if temperature levels continue to rise. International treaties and initiatives, the most important being the Paris Agreement (COP21) adopted in December 2015, aim to restrict the impact of global warming by mitigating carbon emissions. Reducing carbon emissions also contributes to limiting resource depletion and reducing pollution. Sizeable carbon emissions arising from the built environment are attributable not only to the use of built assets – operational emissions (Scopes 1 and 2) – but also to their construction – embodied emissions (Scope 3), see Appendix 2: Glossary. Operational emissions result from energy consumption in the day-to-day running of a property, while embodied emissions arise from producing, procuring and installing the materials and components that make up a structure. These also include the lifetime emissions from maintenance, repair, replacement and ultimately demolition and disposal. More detail on the terminology with respect to embodied, operational and whole life carbon is given in 3.2.4. The built environment industry has so far been addressing mainly operational emissions via reduction targets in building regulations (Part L), planning requirements by local authorities and sustainability assessment rating schemes (BREEAM, LEED, etc.) with the embodied aspect of carbon emissions not being fully addressed. To acquire an overall understanding of a built project’s total carbon impact, it is necessary to assess both the anticipated operational and embodied emissions over the whole life of the asset. Considering operational as well as embodied carbon emissions together over a project’s expected life cycle constitutes the whole life approach. A whole life carbon approach identifies the overall best combined opportunities for reducing lifetime emissions, and also helps to avoid any unintended consequences of focusing on operational emissions alone. For example, the embodied carbon burden of installing triple glazing rather than double can be greater than the operational benefit resulting from the additional pane. Therefore, whole life carbon needs to be effectively integrated into the sustainability agenda in order to achieve a lower carbon future.