Climate change and loss of biodiversity are advancing rapidly, making a transition to a more sustainable society one of the most pressing tasks facing humanity. This special section shines a spotlight on how emotions shape and are shaped by the climate and biodiversity crises, and how they intersect with pro-environmental behavior. To this end, leading sustainability scholars and policy makers articulate what they believe are the most important questions that emotion research should answer to support a sustainable societal transition. Here, we first provide an overview of the articles in the special section, which include a wide range of topics including global analyses of distress related to climate change and biodiversity loss, case studies on emotional experiences toward locally specific instances of climate change consequences and adaptation or mitigation efforts, discussions of the motivational functions of emotions and their potential to drive pro-environmental action, and reflections on how we can make affective science more salient to policy makers in the sustainability domain. In the second part, we summarize the emerging overarching themes that point to promising research objectives and questions for affective sustainability science. Finally, we discuss how the study of sustainability can also be beneficial for the affective sciences. Our hope is that this special section will put sustainability on the research agenda of emotion researchers and stimulate more research in affective sustainability science.