Kyle Harper Avenir Commun Durable (2023-2024) Collège de France Année 2023-2024 Séminaire - A Tree-Ring Retrospective on Volcanoes, Climate and Society Ulf Büntgen Pr. of Environmental Systems Analysis, Department of Geography, University of Cambridge, UK Résumé I will outline how different tree-ring data and methods can be used to better understand the direct and indirect effects of large volcanic eruptions on the Earth's climate system and how past climate variations have impacted ecological and societal systems at different spatiotemporal scales. Although my presentation will have an analytical focus on the past 2000 years, I will also discuss the potential and limitations of reconstructing Holocene climates and its forcing factors. Conceptual emphasis will be placed on interdisciplinary approaches to unravel the human-climate nexus. Ulf Büntgen Ulf Büntgen is a professor of environmental systems analysis at the Department of Geography, University of Cambridge, UK. He is also professor of physical geography at the Department of Geography, Masaryk University in Brno, Czech Republic, and research associate at CzechGlobe, Global Change Research Institute of the Czech Academy of Science in Brno, Czech Republic. Since nearly two decades, he is a dendrochronologist, paleoclimatologist, and global change ecologist. Together with colleagues all over the world, he addresses the following question(s): What are the causes and consequences of past and present changes in diverse, though often intertwined environmental system components, across a wide range of spatiotemporal scales; and how can different tree-ring archives, parameters and techniques be optimised to provide scientific answers to timely research questions of topical relevance at the crossroads of wildlife biology, forest ecology, mycology, (paleo)climatology and human history. Ulf's credo is "Ask the right question(s) and let the data speak".