Professor Müller is Managing Director of Oxford Climate Policy (a not-for-profit company aimed at capacity building for developing country climate change negotiators), and Director of the European Capacity Building Initiative (ECBI), an international initiative for sustained capacity building in support of international climate change negotiations. In the context of the UN climate change negotiations, Müller is an Adviser to the Least Developed Country Group Chair (2011-12) and the Africa Group Chair (2012-13). He participated in the deliberations of the Transitional Committee (TC) for the Green Climate Fund (GCF) as Adviser to the LDC TS members, and is also advising on the Green Climate Fund Board.
At Oxford University he is Convener International Climate Policy Research at the Environmental Change Institute (ECI), Visiting Professor at the Social Sciences Division, and a Member of the Faculty of Philosophy.
Müller received a doctorate in Philosophy from the University of Oxford and was formerly a Research Fellow at Wolfson College and a Lecturer in Logic at the Queen's College, Oxford. He has a Diploma in Mathematics from the Eidgenössische Technische Hochschule (ETH) in Zürich, Switzerland.