Destabilization of carbon in tropical peatlands by enhanced weathering

Enhanced weathering is a carbon dioxide (CO2) removal strategy that accelerates the CO2 uptake and removal from the atmosphere by weathering via the dispersion of rock powder. Warm and humid conditions enhance weathering and among the suggested target areas for enhanced weathering are tropical peatlands. However, the effect of enhanced weathering on peatland carbon stocks is poorly understood. Here, we present estimates for the response of CO2 emissions from tropical peat soils, rivers and coastal waters to changing soil acidity induced by enhanced weathering application. We estimate that the potential carbon uptake associated with enhanced weathering is reduced by 18–60% by land-based re-emission of CO2 and is potentially offset completely by emissions from coastal waters. Our findings suggest that in contrast to the desired impact, enhanced weathering may destabilize the natural carbon cycle in tropical peatlands that act as important carbon sinks and protect against coastal erosion.

Alexandra Klemme, Tim Rixen, Moritz Müller, Justus Notholt, Thorsten Warneke