Sustainability Science is an emerging, transdisciplinary academic field that aims to help build a sustainable global society by drawing on and integrating research from the humanities and the social, natural, medical and engineering sciences. Academic knowledge is combined with that from relevant actors from outside academia, such as policy-makers, businesses, social organizations and citizens. The field is focused on examining the interactions between human, environmental, and engineered systems to understand and contribute to solutions for complex challenges that threaten the future of humanity and the integrity of the life support systems of the planet, such as climate change, biodiversity loss, pollution, and land and water degradation. Since its inception in around the year 2000, and... as expressed by a range of proponents in the field, sustainability science has become an established international platform for interdisciplinary research on complex social problems . This has been done by exploring ways to promote ‘greater integration and cooperation in fulfilling the sustainability science mandate’ . Sustainability science has thereby become an extremely diverse academic field, yet one with an explicit normative mission. After nearly two decades of sustainability research, it is important to reflect on a major question: what critical knowledge can we gain from sustainability science research on persistent socio-ecological problems and new sustainability challenges?