Tom Bury, Applied Mathematics, University of Waterloo
On the Theory and Application of Early Warning Signals for Critical Transitions
Abrupt and often irreversible transitions can be observed in a wide variety of systems including ecological communities, complex disease and social networks. These so-called 'critical transitions' can be brought on by a gradual change in external conditions that quietly reduce the resilience of a system. Despite their seemingly unpredictable nature, generic early warning signals have been proposed which, once verified for a particular system, could provide the means for mitigating or even preventing unwanted transitions. However, in higher dimensions, the typical early warning signals can become amplified, muted, or even reversed, due to the intricate variable interactions in the approach to the transition. In addition, these more complex systems can exhibit a wider variety of transitions to their simplified counterparts. This thesis aims to pin down the mechanisms that cause these particular alterations in early warning signals, which may then work in our favour by helping us characterise the transition being approached. Working alongside models in the social, ecological and biological sciences, we hope to contribute the the challenging task of detecting nearby critical transitions in these fields.