Research: Earth System Resilience

I am fascinated by the co-evolution of the Earth, life, and human societies as a complex and dynamic system, and what this means for our future. My research uses numerical modelling and analysis to investigate Earth System resilience in the past and future, including climate-biosphere feedbacks and tipping points, dynamics and indicators of ecological resilience, and the sustainability of socio-ecological systems.

Since the Earth formed some ~4.6 billion years ago it has experienced many dramatic changes, from the formation of the oceans and then continents to the emergence of life itself at least 3.8 billion years ago. This history presents a puzzle: how did life survive for so long on despite repeated mass extinctions and the threat of long-term climate change? The sun has grown some 30% hotter over those ~4.6 billion years, but despite some large fluctuations the Earth’s climate has not grown hotter in parallel. Is this the impact of life (the self-regulating homoeostasis of ‘Gaia’), a geochemical inevitability (the drawdown of CO2 by the slow dissolution of silicate rocks), or just sheer chance (we’re just the observers lucky enough to be alive to ask the question)? Now humans are causing changes more rapid than the Earth has experienced for many millions of years. What can we do to ameliorate our impact, and what happens if we don’t?

Earth system science aims to answer these questions by examining the relationships between all of the Earth’s processes (including humans forming socio-ecological systems in recent times), while complexity science gives us useful tools for analysing and understanding the stability or otherwise of complex dynamical systems such as the Earth system. The emergent theme is Earth system resilience: the degree to which the Earth system can quickly recover from short-term perturbations and return to its previous state. High resilience implies an ability for a system to withstand shocks, whereas declining resilience would leave the system vulnerable to passing ‘tipping points’ beyond which regime shifts to a new state becomes inevitable.

My research takes Earth system resilience as a central theme, and covers topics including Climate-Biosphere Feedbacks & Tipping Points both in the past and future, Sustainable Socio-Ecological Systems (such as the sustainable intensification of agroecosystems), and the Dynamics & Indicators of Ecological Resilience. You can find a list of current publications coming out of this research here.

Since beginning my PhD in 2011, I’ve worked with many great collaborators, including Prof. Toby Tyrrell (Professor of Earth System Science, Uni. Southampton), Prof. John Dearing (Professor of Physical Geography, Uni. Southampton), Dr. James Dyke (Assistant Director Global Systems Institute, Uni. Exeter), Prof. Tim Lenton (Director Global Systems Institute, Uni. Exeter), Dr. Sarah Cornell (Principal Researcher, Stockholm Resilience Centre), and Prof. Johan Rockström (Director, Potsdam Institute).