Reactive transport modeling, or computer simulations of the transfer of mass and energy through the subsurface, has become a central tool for understanding how Earth’s unique chemical environments are formed, how they function today, and how they might behave in the future. This process-based approach has enabled us to gain a new understanding of a diverse array of Earth processes, from biogeochemical cycles in marine sediments and the factors that control soil formation, to the evolution of contaminated groundwater systems and the engineered containment of nuclear waste. The diverse contributions in this issue will highlight the unique role that reactive transport models have played in advancing our understanding of Earth’s shallow crustal environments and our human interactions with them.
