Sir Crispin Tickell, Government Adviser on the Environment, and former UK Ambassador to the United Nations, came to Cambridge as the last speaker in this series. He discussed the ways in which human living conditions have improved dramatically since the industrial revolution - resulting in dramatic population increase, and subsequent land degradation, water pollution, energy use and abuse, climate change and damage to biodiversity. \This acceleration in the earth's transformation is not sustainable\, he said. He argued that while scientists and environmentalists have successfully won widespread public awareness of the perils of climate change, they now have to do a similar job in enlightening people about the importance of biodiversity, so that we don't take natural systems for granted. (e.g. When we cut down forests, we are destroying areas of trees that hold together the structure of the earth underneath that contains water which in turn sustains plant and animal life etc.) He called for better \global governance\ on this issue, and warned, \We may have to make many changes if we are going to bequeath a healthy Earth to our children.\ (Lecture summary provided by Centre for Sustainable Development.)