The interaction of animals with their environment, particularly plants, is the missing link between biodiversity and climate crises. Regenerating functional ecosystems with healthy animal populations (this is what rewilding is about) is an approach that addresses a systemic problem with a systemic solution. It means addressing biodiversity and climate crises at the same time. The project "Animating the Carbon Cycle (ACC)" will quantify the carbon sequestration impact of rewilding.