On 23 April 2008 the 17th annual EU-Japan summit was held in Tokyo. The summit leaders reaffirmed their willingness for Japan and the European Union to continue addressing climate change, achieving the United Nations’ Millennium Development Goals, and maintaining international peace and security. Both sides considered energy efficiency improvement to be the most cost effective way of addressing climate change in the short term and committed to enhance international cooperation in this field. Japan and the European Union also emphasised the need for strengthening energy security and increased use of sustainable energy options such as renewable energy sources, enhanced oil recovery, clean coal and carbon capture and storage.