Modelling study: Basalt dust on China's farmland could lock away up to 0.79bn t of CO2
Researchers from Tsinghua University and Cambridge estimate the potential and cost of enhanced rock weathering in China – and call for field trials before the method is rolled out widely.
Symbolic image · Photo: Walter Siegmund / Wikimedia Commons, CC BY-SA 4.0 (cropped and resized)
Enhanced rock weathering spreads finely ground rock such as basalt on fields; as the rock weathers, carbon dioxide is drawn from the air and locked away. Zeyu Wang and Fei Teng of Tsinghua University's Institute of Energy, Environment and Economy in Beijing, together with David Reiner of the University of Cambridge, calculated the method's potential for China's croplands. The study was published on 10 October in the journal Communications Earth & Environment; it is an early version that is still subject to editing.
According to the calculations, a single year of basalt dust application could remove between 0.44 and 0.79 billion tonnes of CO2 by 2100. The authors put the net life-cycle cost at 127 to 226 US dollars per tonne. With repeated applications over several years, the method could meet 5 to 30 per cent of the carbon removal China needs by 2060 for its climate goal.
Context: the results are based on model calculations, not field measurements. The authors see the method as an option for China's climate strategy but explicitly call for field trials and better models of processes in soils and rivers. The most suitable areas are in the north-east, the central and southern regions and the east of the country; rock ground finer than is commercially typical offers the best balance between removal and cost.