Tipping Points and Causality in the past Earth system

Summary

Over the past 66 million years, Earth's climate has gradually cooled, with decreasing carbon dioxide levels and temperatures. However, this cooling trend has been interrupted by sudden and extreme climate and carbon cycle changes. These abrupt changes may occur when the Earth system reaches a "tipping point," pushing the system to a new stable state rapidly and unexpectedly. In this PhD thesis, dynamical systems theory and data-driven techniques are combined to investigate tipping points, feedbacks, and complex system dynamics to study how and why these sudden changes occurred in the prehistoric Earth. The research showed that extreme global warming events 50 million years ago were triggered by tipping points. The research also showed that there was a very high association during warm periods of high atmospheric carbon dioxide and temperature which could have increased Earth’s sensitivity to perturbations.