Global concerns over environmental issues have reached unprecedented levels in recent years, with strong evidence linking extreme weather events to human influence. In response, vibrant activist movements have emerged, advocating for urgent environmental action. These movements engage in a spectrum of actions, from normative (e.g., organizing marches) to more extreme and potentially illegal activities (e.g., blocking roads or property destruction). Environmental activism, defined as collective action aimed at advocating for policy changes, has been extensively studied, revealing insights into its dynamics, including the role of education in fostering environmental consciousness and the related behavioral outcomes, including the tendency to radicalization. While radicalization has often been equated with terrorism and, therefore, with violent manifestations, it actually refers to a psychological process that does not necessarily lead to violence and can manifest itself in various contexts, including environmental activism. Although current instances of violent radicalization in environmental movements are rare, there is a growing concern, highlighted by public institutions and scholars, that escalating climate crises and perceived inefficacy of normative measures may lead to future radicalization. In this report, we discuss how to foster peaceful climate change activism and reduce the risk of radicalization through educational programs by reviewing definitions of the wide spectrum of environmental activism and the theoretical approaches used to study them, discussing the effectiveness of different actions and the portrayal of climate change activists in the media, and focusing on environmental litigations and the role of environmental literacy as a potential tool to empower climate change movements.