UKGBC’s vision for a sustainable built environment is one that mitigates and adapts to climate change.
The built environment contributes around 40% of the UK’s total carbon footprint. Almost half of this is from energy used in buildings (eg plug loads and cooking) and infrastructure (eg roads and railways) that has nothing to do with their functional operation. Opinion varies over the built environment industry’s responsibility to address this energy ‘in use’. The low carbon routemap targeted by the UK’s Green Construction Board (GCB) does not include ‘in use’ emissions, but several definitions of zero carbon buildings do include them.
Despite erratic annual variations, the carbon footprint of the built environment has reduced since 1990. Insulation installation rates between 2008 and 2012 and decarbonisation of grid electricity both contributed to this downward trend.
Newly constructed buildings are more energy efficient, but 80% of buildings in 2050 have already been built, so a major priority is decarbonising our existing stock. Yet Government policies aimed at improving the efficiency of existing buildings have scaled back dramatically, and insulation installation rates have stalled.
Direct emissions from fuel use in existing buildings rose for the second year running in 2016, mainly due to heating. Heating alone results in 10% of the nation’s carbon footprint and homes are more significant than all other building types put together. Decarbonising our heat supply is one of the big policy challenges ahead. Another major challenge is the carbon embodied through construction. Annual embodied emissions alone are currently higher than the GCB’s target for total built environment emissions by 2050.
Finally, the built environment is crucial to allow us to adapt to changing and increasingly extreme climatic conditions. Yet several million properties are in areas at risk of flooding, and the risk of overheating remains very high especially in social housing. Adaptation measures including sustainable drainage systems and flood risk alleviation should be prioritised further.