Enhanced rock weathering involves spreading crushed basalt over farmlands to allow the interaction of minerals and atmospheric CO2; the Sheffield study found that it could help to eliminate up to 2 billion tonnes of CO2 per year.
How does it work?
In the process of basalt weathering (enhanced rock weathering) in water-rich soil, CO2 is turned into bicarbonate which can eventually reach the ocean. Studies have demonstrated reproducibility of results obtained from four years’ trials conducted in Illinois using 50 tonnes per hectare of the basalt.
Does it work in practice?
Results differ. EarthSky reports that it is difficult to conduct direct measurements of the amount of CO2 eliminated; hence estimates vary from less than 0.02 to over 10 tonnes of CO2 per hectare.
Does it have a future?
The Sheffield study estimated costs to range from US$80 to 180 per tonne, which is comparable to other carbon removal methods. However, large-scale trials and verification are needed in future before carbon credits can be trusted in the carbon market.
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