The Earth System Science Research School (ESSReS) is an international and interdisciplinary research school for 23 PhD students at the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI) and their partner universities: University of Bremen and Jacobs University Bremen. ESSReS combines observations, modelling, and data analysis in order to decipher the Earth’s complex climate system. Structured training, international exchange and supervision support interdisciplinary research at an early stage of the scientific career.