Alex J. Farnsworth
Alex Farnsworth is a palaeoclimate modeller and meteorologist at the University of Bristol, and visiting Professor at the Institute of Tibetan Plateau Research (ITP), Chinese Academy of Sciences, Beijing, China. One of his primary areas of research includes investigating paleogeographic uncertainty, the role of atmospheric CO₂ levels in shaping historical climate patterns and, in particular, monsoon dynamics. He uses state-of-the-art climate models to reconstruct prehistoric environments, offering insight into constraining how future climates might evolve. He is widely recognized for his interdisciplinary approach, bridging geology, climatology, biogeography and numerical modeling to better understand how climate and the environment co-evolve through geologic history.
Evolution of ENSO over the past 541 million years and its contribution to Earth's largest mass extinction
El Niño–Southern Oscillation (ENSO) is a principal mode of climate variability that exerts a significant influence on the Earth’s climate system. It modulates surface temperatures, governs hydrological cycles, and alters the frequency and intensity of extreme weather events on a global scale. Although much is known about its modern behaviour, less is understood about its historical behaviour, which may provide clues to its future response.
In the first part of this study, we explore the variability of ENSO over the past 541 million years, a period during which the Earth evolved from a supercontinent into fragmented continents. Next, we dynamically examine periods marked by substantial changes in ENSO behaviour, considering the influence of basin size as well as uncertainties in palaeogeography and atmospheric CO₂. Finally, we highlight the role of ENSO in the largest mass extinction event recorded, the Permo-Triassic boundary (approximately 251 million years ago), when over 90% of all life forms perished.
Until recently, the ultimate driver of the end-Permian mass extinction had been a matter of considerable debate. Here, we employed a multiproxy and palaeoclimate modelling approach to establish a unifying theory. Our findings elucidate the heightened susceptibility of the Pangean world to prolonged and intensified El Niño events, which induced an extinction state through reduced carbon sequestration. This reduction initiated a positive feedback loop that resulted in a warmer hothouse climate and, consequently, stronger El Niño conditions, ultimately leading to global extinction.
