There a new book, "Is the Planet Full?" by Oxford University Press, that provides and update and some interesting new perspectives on the question of how much impact we are having on the Earth, and how much more impact can the Earth support. I have a chapter, "the metabolism of a human-dominated planet", that takes a quantitative metabolic approach to the question "how big is humanity?". It examines human metabolism throughout human history, ranging from hunter-gatherer society through pre-industrial agricultural societies through to modern industrial societies. The introduction chapter to the book can be downloaded here, and my chapter can be accessed here. The book can be purchased from the OUP website or most other book suppliers.
Last weekend I had a wonderful family weekend at the Hay Book Festival, where I presented on my chapter together with Charles Godfray (who talked on food supply). The slides for the talk can be downloaded here and the audio file can be downloaded here. The talk explores a couple of ideas further, including the intriguing idea that much of Eurasia stalled in metabolic growth after the collapse of the Roman Empire for 1700 years before the industrial revolution.
Yadvinder Malhi is an ecosytem ecologist and Professor of Ecosystem Science at Oxford University