Prior to his present appointment, Professor Clift was Head of the Department of Chemical and Process Engineering at the University of Surrey for 10 years. He is a Fellow of the Royal Academy of Engineering, of the Institution of Chemical Engineers and of the Royal Society of Arts, and an Honorary Fellow of the Chartered Institute of Waste and Environmental Management. He is also Visiting Professor in Environmental System Analysis at Chalmers University, Gothenburg, Sweden and a Director of the Merrill Lynch New Energy Technologies investment trust. In 2005 he completed a 9 year term as a member of the Royal Commission on Environmental Pollution, and acted as Expert Adviser to an enquiry by the House of Lords Science and Technology Committee in "Energy Efficiency". In 2006,he begins appointment as a member of the Science Advisory Council of the Department of the Environment, Food and Rural Affairs (Defra). He is a past member of the UK Ecolabelling Board, and of the Royal Society/Royal Academy Working Group set up at the instigation of the Department of Trade and Industry to examine, inter alia, the risk and regulatory issues raised by nanotechnology.

In 1994 Professor Clift was awarded an OBE for his services to science and technology. In 2003 he was recognised as a Distinguished Professor by the University of Surrey and also received the Royal Academy of Engineering's Sir Frank Whittle Medal "for outstanding and sustained engineering achievement contributing to the well being of the nation".  Professor Clift was honoured in the 2006 New Year's Honours as a Commander of the British Empire (C.B.E.) for his services to the environment.