Oil Crises and Climate Challenges: 30 Years of Energy Use in IEA Countries This publication examines how energy efficiency and other factors such as economic structure income lifestyle prices and fuel mix have shaped developments of energy use and CO2 emissions in IEA countries since the IEA was founded 30 years ago. The study presents some challenging findings e.g. that the rate of energy savings in IEA economies has slowed since 1990. It provides a rich set of data and insights that help to increase the understanding of how energy efficiency and lower carbon fuels can be used to achieve a more sustainable future.