Edward Rhodes, University of Sheffield, Department of Geography, Sheffield, S10, United Kingdom, Andrew Ivester, University of Sheffield, Department of Geography, Sheffield, United Kingdom, James Francis Dolan, University of Southern California, Department of Earth Sciences, Los Angeles, CA, United States, Russ James Van Dissen, GNS Science, Lower Hutt, New Zealand and Timothy Little, Victoria University of Wellington, School of Geography, Environment and Earth Sciences, Wellington, New Zealand