Sir Crispin Tickell is Warden of Green College, Oxford; Chancellor of the University of Kent at Canterbury; Chairman of the Climate Institute of Washington, DC; Director of the Green College Centre for Environmental Policy and Understanding; Chairman of the Government's Advisory Committee on the Darwin Initiative; and Convenor of the Government Panel on Sustainable Development.

Sir Crispin was a member of the Diplomatic Service. He was Chef de Cabinet to the President of the European Commission (1977–80), Ambassador to Mexico (1981–83), Permanent Secretary of the Overseas Development Administration (1984–87), and British Permanent Representative to the United Nations (1987–90). He was also President of the Royal Geographical Society (1990–93), and Chairman of the International Institute for Environment and Development (1990–94).

He is the author of Climatic Change and World Affairs (1977 and 1986), and Mary Anning of Lyme Regis (1996). He has contributed to many other books on environmental issues (including human population increase and biodiversity). His interests go very wide, and include business and charities. More personally he cherishes mountains, pre-Colombian art, and palaeo-history.