An overview of climate change mitigation opportunities in the world's buildings is presented, based on the key building-specific findings of the Fourth Assessment Report from the Intergovernmental Panel of Climate Change. Buildings and the building stock can play a major role in mitigating climate change in the short- to medium-term, since substantial reductions in CO2 emissions from their energy use can be achieved over the coming years.

Co-benefits rarely enter quantitative decision-support frameworks, often because the methodologies for their integration are lacking or not known. This review fills in this gap by providing comprehensive methodological guidance on the quantification of co-impacts and their integration into climate-related decision making based on the literature. The article first clarifies the confusion in the literature about related terms and makes a proposal for a more consistent terminological framework, then emphasizes the importance of working in a multiple-objective–multiple-impact framework.

This report is the first report of the ‘Energy Savings 2030’-project which seeks to help the Coalition for Energy Savings to produce a robust and timely input to the 2030 policy discussion. It brings together and summarises recent empirical evidence on costs and benefits of energy efficiency measures. The evidence gap in terms of reliable ex-post data is well known. In the majority of cases results from ex-ante modelling studies inform the debate. The research carried out for this report confirms the persistent gap in publicly available ex-post evaluations of energy efficiency programmes.