Environmental and sustainability sciences require cooperation across the great divide, i.e. between natural and social sciences and humanities. The research focus of the Institute of Social Ecology (SEC) is positioned exactly on this interface. SEC is renown and international visible through its interdisciplinary and transdisciplinary research on the interaction between social and natural systems in the context of globalisation, global change and sustainable development in cooperation with diverse scientific communities and stakeholders from social, economic and political sectors of society. SEC has played a significant role in shaping international sustainability discourse with the concepts of 'social metabolism' with material flow and energy flow analysis (MEFA); 'colonisation of natural systems' with land-use indicators (i.e. HANPP); socio-ecological systems modelling; and its focus on environmental history and socio-ecological transformations.