He was a member of the UNESCO/IUPAC International Chemistry Council for four years and served on President Nelson Mandela's National Commission on Higher Education.
In the transition to a democratic South Africa Garbers served as a member of the Working Group of the ANC, Congress of South African Trade Unions (Cosatu), and Sanco on the Science and Technology Initiative, the Advisory Group to the Minister of Arts, Culture Science and Technology.
He was a member of the Unesco/IUPAC International Chemistry Council for four years from 1995 and during 1995/96 served on President Nelson Mandela's National Commission on Higher Education.
He continued his studies at the University of Zurich, Switzerland under Nobel Laureate Paul Karrer, completing the D.Phil.
Honorary doctorates were conferred on him by the Universities of South Africa (1989), Cape Town (1990), Stellenbosch (1991), and Pretoria (1994).