Exploratory Review on Environmental Aspects of Enhanced Weathering as a Carbon Dioxide Removal Method

Abstract

The accumulation of carbon dioxide in the atmosphere due to fossil fuel burning and deforestation has caused global warming and an increase in extreme weather events. To complement the shift towards clean energy, it is crucial to adopt methods for carbon dioxide removal, known as negative emission technologies. Enhanced weathering is one such approach that involves accelerating the natural process of rock weathering by spreading finely ground rocks over large areas, such as agricultural land or coastal areas. This exploratory review paper provides an overview of the fundamental mechanisms behind enhanced weathering, and outlines the techniques for its implementation. The environmental benefits of enhanced weathering are highlighted, including carbon dioxide removal, and improvement of soil fertility. Furthermore, potential impacts on ecosystems and biodiversity are examined, along with the effects on water, soil and air quality. The paper also considers the risks and challenges associated with large-scale implementation and long-term stability of enhanced weathering. Additionally, the integration of enhanced weathering with Sustainable Development Goals is explored, along with the potential co-benefits and trade-offs with other sustainability objectives. To conclude, this exploratory review paper summarizes the key findings and proposes avenues for further research in this field of enhanced weathering.

A review of measurement for quantification of carbon dioxide removal by enhanced weathering in soil

“…Firstly, it is not possible to distinguish between an organic and inorganic carbon effect on CO 2 efflux via measurement of CO 2 alone. Secondly, organic carbon fluxes dominate this measurement, and are around an order of magnitude higher (~25 tCO 2 .ha -1 .yr -1 ; Weil and Brady, 2017;Lockhart et al, 2023) than any reduction that might be seen due to changes in inorganic fluxes from EW (<2 tCO 2 .ha -1 .yr -1 , normalized for 50 t rock powder/ha; Vandeginste et al, 2024;see SI). This means that a reduction in efflux from bicarbonate production during EW would be unlikely to be detected relative to a control, and that these measurements will be noisy (Weil and Brady, 2017).…”

Table_1.DOCX

“…Firstly, it is not possible to distinguish between an organic and inorganic carbon effect on CO 2 efflux via measurement of CO 2 alone. Secondly, organic carbon fluxes dominate this measurement, and are around an order of magnitude higher (~25 tCO 2 .ha -1 .yr -1 ; Weil and Brady, 2017;Lockhart et al, 2023) than any reduction that might be seen due to changes in inorganic fluxes from EW (<2 tCO 2 .ha -1 .yr -1 , normalized for 50 t rock powder/ha; Vandeginste et al, 2024;see SI). This means that a reduction in efflux from bicarbonate production during EW would be unlikely to be detected relative to a control, and that these measurements will be noisy (Weil and Brady, 2017).…”