Andy Dugmore studies long term records of environments and archaeology to understand the dynamics of complex socio-ecological systems- what creates resilience (for whom, at what cost and for how long), and why do threshold-crossing events take place? A central theme is the development and application of tephrochronology- a dating technique based on the identification and correlation of volcanic ash layers. Tephra provide outstanding ways to integrate environmental records, history and archaeology and cm-scale layers also preserve early warning signals of landscape tipping points - abrupt and major shifts from one state to another.