David Thomas is Professor of Geography at the University of Oxford and a Fellow of Hertford College. Sallie Burrough is a science writer and Honorary Research Associate in the School of Geography and the Environment at the University of Oxford. Nicholas Drake is Professor of Physical Geography at Kings College London. Marion Meyer is Professor of Plant Science at the University of Pretoria. Troy Sternberg is a Senior Researcher in the School of Geography and the Environment at the University of Oxford.