This chapter first introduces concepts of emotions as powerful triggers for activism in environmental movements, analysing emotions catalysing and diffusing activism across places, cities, and countries. It explores the role of emotions in shaping collective identity and solidarity within environmental activism. Drawing on literature from International Relations and Social Movements Studies, it examines how emotional spaces form through shared experiences. Emotions such as fear, anxiety, and hope are analysed as both interconnected and contradictory, often working together to drive resistance. The concepts of climate anxiety and climate justice are discussed in depth. By offering a holistic view of emotional dynamics, this chapter provides a blueprint for key discussions and analyses in Chaps. 4 , 5 , and 6 , providing a framework for understanding emotional responses to environmental challenges.