Mradi wa Umoja wa Mataifa Kuhusu Mazingira
Alifuatwa na Elizabeth Dowdeswell (1992–1998), Klaus Töpfer (1998–2006), Achim Steiner (2006–2016), Erik Solheim (2016-2018), Joyce Msuya (2018-2019) na Inger Andersen (2019–sasa).