Climate change represents a widespread threat to both humans and nonhumans and demands strong global responses and actions to mitigate them. Given the nature of these threats, communication scholars are in a unique position to contribute meaningfully to solutions and mitigation efforts by crafting effective public communication campaigns around climate change and sustainability. The articles included in this Special Section explore the various challenges and opportunities surrounding effective climate and sustainability communication campaigns. A primary aim of this Special Section is to move climate change communication scholarship beyond its early focus on media coverage of climate change. Instead, the focus is on research that operates in an updated paradigm and reality, acknowledging, for example, the blurring lines between informative and persuasive media content and between mass-produced and user-generated content. The articles were drawn from a special postconference jointly sponsored by the Environmental Communication, Political Communication, and Health Communication divisions of the International Communication Association and represent a diversity of theoretical and methodological viewpoints from international scholars.