Evidence based policy making is increasingly important, as policy makers are faced with policy dilemmas and need scientific input for policy development. Recent emergencies with a serious public impact (volcanic eruptions in Europe, earthquake and tsunami in Japan etc.) have shown that we need to speed up the interaction between science and politics in urgent situations. The purpose of the session would be to address via interactive discussions how to bring science even closer to policy making, what are the main challenges, and to share experiences and compare different systems in the EU and the US.