Achim Steiner was appointed Senior Fellow at the Oxford Martin School, University of Oxford, in January 2026, where he leads a global programme on ‘Security Futures’. He previously served as United Nations Under-Secretary-General and Administrator of the United Nations Development Programme (2017–2025), leading the UN’s largest development agency across more than 170 countries.

Earlier, he served as Executive Director of the United Nations Environment Programme (2006–2016), where he pioneered green economy policies and helped establish the UN Environment Assembly. His career has also included leadership roles at IUCN, the World Commission on Dams, the UN Office at Nairobi and the University of Oxford.

Steiner currently chairs the Hamburg Sustainability Conference and serves on several international councils and boards. Born in Brazil and holding Brazilian and German nationality, he studied at Oxford and SOAS and IDOS.