Earthcasting the future Critical Zone

Abstract

Abstract As humans continue to impact the Critical Zone, we need to project how our environment will evolve into the future. To model such change requires the ability to simulate interactions among the lithosphere, pedosphere, hydrosphere, biosphere, and atmosphere — including the activities of humans. Such projections, which some have called earthcasts, must be made with mechanistic models that capture the important phenomena, as well as scenarios of human behavior. As an example, we present earthcasts of future weathering in the mid-continent of the USA into the next century of projected warming. Rates of sequestration of CO2 from the atmosphere due to weathering will change in the future as carbonate and silicate minerals are dissolved or precipitated in soil. The downward or upward advance of the carbonate reaction front in the soil is an analogue of the oceanic lysocline. Like the movement of the oceanic lysocline in response to oceanic acidification, this terrestrial lysocline will likely move due to fluxes of CO2 driven by human activity. Understanding this and other responses to perturbations will best be achieved using multiple models for earthcasting.