Climate change is a firmly established and prominent issue of concern for the European Union. The EU became a collective agent of securitisation over time, increasingly engaging in speech acts defining climate change as a threat. These speech acts have driven forward agreed European policy measures and have informed EU positions in international climate negotiations. This piece examines how climate change became securitised and traces the historical development of the EU as an agent of collective securitisation in this domain. It argues that the EU has become a more unified, collective actor over time, that it has engaged in recursive interaction with multiple (internal and external) audiences to drive the securitisation of climate change, and that a new securitised status quo had been achieved by the mid-to-late 2000s. This new status quo positions climate change as central to the EU's security agenda.