Master of Science, St. Petersburg University, Russia, 1972. Disseminated Intravascular Coagulation, Imperial College, England, 1984. Doctor of Philosophy, London University, England, 1986.
Chief geologist Geological Survey Kenya, 1974—1979. Chief research officer Kenya Marine & Freshwater Research Institute, Mombasa, 1980—1987. Professor University Nairobi, since 1988.
Advisor United Nations, Global, since 2004. Director Global Change Research Africa, Nairobi, since 1997.
Married Lilian Adoyo, July 31, 1975. 1 child Elizabeth David Christine.