Susan Trumbore

Germany/USA

2020 Balzan Prize for Earth System Dynamics

For her outstanding contributions to the study of the carbon cycle and its effects on climate, and for pioneering the use of radiocarbon measurements in Earth-system research.

Professor Trumbore earned her Bachelor of Science in Geology at the University of Delaware in 1981 and a doctoral degree in Geochemistry at Columbia University in 1989. She was a PhD student of Wallace Broecker, recipient of the Balzan Prize in the Science of Climate Change in 2008. She held postdoctoral fellowships with the Swiss Federal Institute of Technology ETH in Zurich and the Lawrence Livermore National Laboratory. She joined the faculty at the University of California, Irvine in 1991.

She is currently a director at the Max Planck Institute for Biochemistry in Jena (Germany) and a professor of Earth System Science at the University of California, Irvine.

Her early work on the input of 14C Bomb Pulse as a transient tracer that is now present at different concentrations in different components of the global carbon system has been a breakthrough in the field. She not only provided many of the initial insights into the use of this tracer, but also developed the technology that allowed its measurement. She is universally recognized as the world’s leading authority in applying radiocarbon dating to environmental science, including climate change research.

Susan Trumbore’s research is highly interdisciplinary, combining in a novel way field ecology, plant physiology and soil science, with the methodological development of Accelerated Mass Spectrometry (AMS) as a key tool for studying the flow of carbon in the Earth System.

Her research is global in scope, ranging from forest and grassland ecosystems in Germany to tropical rainforests and savannahs in South America and Africa and boreal forests in Canada. With a prestigious Advanced Grant awarded to her by the European Research Council (ERC) she is currently leading a project to synthesize the factors that control the ages and transit times of carbon stored in soil organic matter in ways that can best test and inform global carbon climate models. This is true frontier research as currently predictions of future soil carbon storage represent one of the largest uncertainties in these models.

The new understanding brought about by her research is also highly useful for determining the potential to manage soils to store more carbon and mitigate atmospheric carbon dioxide rise.

Her studies of carbon flow also provide fundamental information about how ecosystems operate. In this context, Susan Trumbore and her co-workers have used radiocarbon to demonstrate the great age and slow growth rates of some tropical tree species and to determine the age of carbon stores used by trees to grow during periods of low carbon supply. Experimental studies applying low levels of a radiocarbon label can now, as a result of her work, be used to study rates of carbon fixation in groundwater Bacteria and Archaea and to trace carbon flow through plant and microbial communities.

Since moving to Germany in 2009, Trumbore’s research activities have expanded to include a broader range of approaches to study the biochemical processes that control how energy and water as well as carbon are exchanged between terrestrial ecosystems and the atmosphere, and their influence on climate. Through this frontier research she contributes to ongoing studies of how large soy farms in the Amazon lead to deforestation.

Susan Trumbore has been a constant source of inspiration to students and young researchers, mentoring numerous PhD students and postdocs. She is an award-winning Earth system scientist, distinguished as a Fellow of the American Geophysical Union and a member of the US National Academy of Sciences and the German National Academy of Sciences Leopoldina; she is a recipient of the Benjamin Franklin Medal in Earth and Environmental Science.