The German Advisory Council on Global Change (WBGU), co-chaired by IDOS Director Prof. Anna-Katharina Hornidge, published a short paper on Security: What we need to talk about. The paper argues that national security and global sustainability are mutually dependent and that Europe must bolster its ability to act if it is to stand up for common values both internally and externally. Based on this, the WBGU raises a number of questions to stimulate debates on the security situation and its relation to sustainability issues, ranging from how the destruction of nature and climate change can finally be addressed with top priority to protecting democracies and building international alliances for sustainable transformation.