Enhanced weathering for carbon dioxide removal in phosphorus poor systems

Early and sustained deployment of a mix of Carbon Dioxide Removal (CDR) technologies is needed to keep global climate warming below 2°C. Enhanced weathering (EW) is a land-based CDR option that accelerates the natural process of carbon dioxide fixation by weathering by soil amendment with crushed rocks. EW has a low technical risk, no direct impacts on water resources, and can be co-deployed with other land use practices - but its CDR potential is only partly assessed as positive effects on soil fertility have been omitted.

To address this gap, we use a land surface model coupled to a weathering model to explore the CDR potential of EW from the release of phosphorus (P) contained in basalt rock soil amendments. The highest CDR potential of EW can be expected in tropical systems, which are characterized by low soil supply of plant-available P. We hypothesize that EW provides a key source of additional P to increase carbon storage in tropical forests.