A global account of the grassroots environmental movements on the frontlines of the climate crisis. Environmentalism from Below takes readers inside the popular struggles for environmental liberation in the Global South. These communities--among the most vulnerable to but also least responsible for the climate crisis--have long been at the forefront of the fight to protect imperiled worlds. Today, as the world's forests burn and our oceans acidify, grassroots movements are tenaciously defending the environmental commons and forging just and sustainable ways of living on Earth. Scholar and activist Ashley Dawson constructs a gripping narrative of these movements of climate insurgents, from international solidarity organizations like La Via Campesina and Shack Dwellers International to local struggles in South Africa, Colombia, India, Nigeria, and beyond. Taking up the four critical challenges we face in a warming world--food, urban sustainability, energy transition, and conservation--Dawson shows how the unruly power of environmentalism from below is charting an alternative path forward, from challenging industrial agriculture through fights for food sovereignty and agroecology to resisting extractivism using mass nonviolent protest and sabotage. An urgent, essential intervention, Environmentalism from Below offers a hopeful alternative to the gridlock of UN-based climate negotiations and the narrow nationalism of some Green New Deal efforts. As Dawson reminds us, the fight against ecocide is already being waged worldwide. Building on longstanding traditions of anticolonial struggle, environmentalism from below is a model for a people's movement for climate justice--one that demands solidarity.