Climate movements are increasingly using a positive approach to raising awareness about climate change. This article aims at analyzing the psycho-social issues at stake in positive communication. It explores anxieties and feelings of guilt raised by the climate crisis, and defense mechanisms used among ecologists, as well as by the rest of the population. Looking at anxiety as socially instituted, the article describes social defense systems at work in interactions between ecologists and non-ecologists. Finally, it suggests that conceptions of social change among climate movements may be bound to the way activists deal with their own anxiety.