This essay aims to study the thought of Seyyed Hossein Nasr, an Iranian Muslim philosopher from the Traditionalist/Perennialist school of thought, on the environmental crisis and its cultural-historical roots. Author of a pioneering book on the relationship between human being and nature, Nasr was among the first thinkers to interpret the environmental crisis from a religious perspective. The essay will show how Nasr, drawing from Western and Eastern sources, gradually developed an increasingly Islamic reading of the problem and possible ways out, focusing his reflection on the concept of the human being as God’s vicar on earth (khalifat Allah fi-l-‘arḍ), guardian of nature and responsible to it. Nasr warned against the misuse of technology, but without demonising it as a whole. He proposed the idea of sustainable development, for which the human being is responsible by virtue of his role as God’s vicar on earth.