Todd A. Ehlers

The 2018 Ralph Alger Bagnold Medal is awarded to Todd A. Ehlers for original and fundamental contributions to our understanding of the coupling between climate, tectonics and erosion, and for outstanding community leadership in geomorphology.

Todd Ehlers is a leading geomorphologist who has delivered several fundamental game-changers in Earth surface science. His research can be characterised as ambitious and interdisciplinary, involving the most modern and exciting parts of tectonics, climate science, modelling, and biology. Ehlers has always seen the big picture of what problems are important, interesting, and tractable. He is able to do so because his science is based on a firm foundation of strong field observations and analytical techniques (including cosmogenic and thermochronologic methods), as well as particularly rigorous numerical and analytical modelling. There are few ideas or hypotheses beyond Ehlers’ reach: his signature combination of modelling and other approaches has led to numerous advances in geomorphology and allied fields, including a significant increase in our understanding of the role of climate and erosion in the dynamic evolution of mountain belts. Using thermochronometry, cosmogenic nuclide dating and landscape evolution modelling, he has made fundamental contributions toward quantifying the impact of Quaternary glaciations on the topography of mountain ranges. His work has also significantly advanced our understanding of glacial erosion processes.

Ehlers is, moreover, a dedicated contributor to science as a whole. He has acted as editor-in-chief for the field’s leading journals, has organised scientific conferences, contributed substantially to steering science-policy and taken leadership in national and international research programmes.