Iran’s regime has survived war, sanctions, and uprising. Environmental crises may bring it down.

The anti‑government protests sweeping across Iran, from major cities to rural towns, are fueled by anger over economic collapse and political repression. But beneath the headlines of currency devaluations and street clashes lies a deeper, more permanent driver of dissent: ecological calamity.

Decades of ignoring scientists, persecuting activists and greenlighting corrupt development schemes have triggered a water crisis so severe that President Masoud Pezeshkian warned in November that...