Carl Steefel is currently a Senior Scientist at Berkeley Laboratory in the Energy Geosciences Division, Earth and Environmental Sciences Area. He also serves as head of the Geochemistry Department. He has over 40 years of experience in developing models for multicomponent reactive transport in porous media and applying them to topics related to geologic hydrogen, terrestrial geochemical fluxes, water-rock interaction, chemical and enhanced weathering, and reactive contaminant transport. Recent work has focused on modeling of geologic hydrogen and geochemical transport through clay-rich rocks. He is the principal developer of the CrunchFlow software, which won an R&D100 Award in 2017. He was named an AGU Fellow in 2019 and received the Berkeley Lab Director’s Award for Exceptional Scientific Achievement in 2020. He currently serves as an Associate Editor for Geochimica et Cosmochimica Acta and formerly served as a Specialty Chief Editor for Frontiers of Water.