Datasets and codes for the peer review article E et al. (2025) "Predicting Salinity and Alkalinity Fluxes of U.S. Freshwater in a Changing Climate: Integrating Anthropogenic and Natural Influences Using Data-Driven Models"

Climate change is an ongoing and intensifying threat. Previous studies indicate that U.S. rivers are undergoing salinization and alkalinization driven by both natural (e.g., temperature and precipitation) and anthropogenic (e.g., population density) factors. In this study, random forest models were developed to predict how salinity (i.e., sodium) and alkalinity fluxes from 226 U.S. rivers will vary with changing population density and climatic forcings (i.e., temperature and precipitation) from 2040 to 2100 across three socioeconomic development pathways. The models predicted a lower future sodium flux in the northern U.S., likely due to reduced winter road salting under projected warmer winters. In the southern and western U.S., where road salting is uncommon, the models predicted little to no change in future sodium flux; however, a projected warmer and drier climate might exacerbate soil salinization in these regions. The models also indicated that carbonate weathering rates are inhibited when temperatures exceed 10 °C, leading to a lower future alkalinity flux in carbonate-rich watersheds under high temperatures. In siliciclastic-dominated or organic carbon-rich watersheds, rising temperatures are associated with increased riverine alkalinity flux, likely through the acceleration of silicate weathering and the decomposition of soil organic carbon. Higher precipitation and enhanced transport capacity were generally deemed to contribute to increased solute fluxes before reaching a plateau. This study underscores the urgency for policymakers and scientists to adapt strategies for managing U.S. rivers, focusing on mitigating the impacts of river salinization and shifts in riverine alkalinity driven by global warming.