Enhanced rock weathering — A nature-based solution for climate mitigation

Much of Paul Younger’s work focused on nature-based solutions that addressed environmental problems, especially relating to removal of contaminants from minewaters. Enhanced Rock Weathering (ERW) has emerged during the last few years as a new paradigm, taking advantage of natural processes of rock weathering to remove CO2 from the atmosphere. This approach makes use of existing infrastructure in mining and processing silicate rocks, especially those used as aggregates in the construction industry. Weathering of silicate minerals has long been known to influence the Earth’s atmospheric CO2 content, and the process of ERW artificially enhances this by crushing the rock to increase its reactive surface area, prior to application to soils. The key challenges include verification of claims for CO2 removal, and scaling up production to meet the need to remove billions of tonnes of CO2 globally. Although multidisciplinary, these challenges are similar to those associated with widespread deployment of passive minewater treatment systems, and are addressed using sound knowledge of mineralogy and geochemistry.