Humans have affected practically all ecosystems on earth. Over the past 200 years, mankind’s emissions of greenhouse gases into the Earth’s atmosphere have changed its radiative properties and are causing a rise in global temperatures which is now modifying Earth system functions globally. As a result, the 21st-century is faced with environmental changes from local to global scales that require large efforts of mitigation and adaptation by societies and ecosystems. The causes and effects, problems and solutions of global change interlink biogeochemistry, Earth system functions and socio-economic conditions in increasingly complex ways. To guide efforts of mitigation and adaptation to global change and aid policy decisions, scientific knowledge now needs to be generated in broad transdisciplinary ways that address the needs of knowledge users and also provide profound understanding of complex socio-environmental systems.