This chapter contextualizes the topic of eco-anxiety by linking it to the anxiety culture phenomenon and the Anthropocene theoretical framework. The rise of eco-anxiety is directly related to the rise of anxiety levels over the last few decades and to long-lasting trends in the Earth system. The chapter explains the three main factors that make eco-anxiety a pervasive feature of life in the Anthropocene: the growing empirical data on the rapidly degrading state of the planet; the increasingly ubiquitous effects of global environmental changes; and the increasing number of fictional productions on ecological issues and their impacts on human and non-human beings. It also categorizes eco-anxiety as a threat-related ecological emotion and explains that even though it is not necessarily a new phenomenon, it increasingly affects people on a global scale and across different socio-demographic categories, albeit to different degrees.