Rupert is the founder and co-Director of the Climate Majority Project. He has also been a spokesperson, national parliamentary candidate, European parliamentary candidate and councillor for the Green Party of England and Wales, and former chair of the ecological think tank Green House.

Rupert was Reader of Philosophy at the University of East Anglia in Norwich. He specialised in Wittgenstein, philosophy of film, ecological and political philosophy and has published extensively in these fields. His most recent book is Transformative Adaptation – Another world is still just possible.