Much has been written about the challenges of tackling climate change in post-political times. However, times have changed significantly since the onset of the debate on post-politics in environmental scholarship. We have entered a politicised, even polarised world which, as this article argues, a number of voices within the climate movement paradoxically try to bring together again. This article scrutinises new climate movements in a changing world, focusing on the School Strikes for Climate in Belgium. It shows how the movement, through the establishment of an intergenerational conflict line and a strong politicisation of tactics, has succeeded in putting the topic at the heart of the public agenda for months on end. By claiming that we need mobilisation, not studying, the movement went straight against the hegemonic, technocratic understanding of climate politics at the time. However, by keeping its demands empty and establishing a homogenised fault line, the movement made itself vulnerable to forms of neutralisation and recuperation by forces which have an interest in restoring the post-political consensus around technocratic and market-oriented answers to climate change. This might also partly explain its gradual decline. Instead of recycling post-political discourses of the past, this article claims, the challenge is to seize the ‘populist moment’ and build a politicised movement around climate change. One way of doing that is by no longer projecting climate change into the future but reframing the ‘now’ as the moment of crisis which calls on us to build another future.