Global Rock C-Sink

The weathering of large quantities of small silicate rocks helps to reduce greenhouse gases in the atmosphere. Usually, weathering is a slow natural process in which minerals chemically bind CO2. However, as a highly scaled-up technology, it can also be used for so-called negative emissions to limit climate risks.

The natural weathering of silicate rocks binds significant amounts of atmospheric CO2 in the form of dissolved inorganic carbon, which eventually ends up in the ocean or precipitates as carbonate. Therefore, weathering of silicate rocks is an important feedback mechanism for atmospheric CO2 and influences climate on geological time scales. By grinding the silicate rock, the reactive surface area can be increased. By exposing the rock to an environment favourable for weathering, e.g. the plant root zone (rhizosphere) or the surface water of the oceans, the weathering process can be accelerated and thus also the uptake of CO2 from the atmosphere.

One advantage is that rock weathering does not compete for land, e.g. with agriculture, unlike biomass-based negative emission scenarios such as short rotation coppice or afforestation. Instead, rock weathering generates agricultural co-benefits by providing important macro- and micronutrients to the soil. The addition of primary minerals stabilises soil organic carbon. Finally, alkaline reaction products released into water bodies can actively counteract ocean acidification and promote additional oceanic carbon removal.

The Global Rock C-Sink Guideline from Carbon Standards International now allows us to standardise and certify this process and thus calculate a C-sink potential for rock weathering and certify corresponding carbon sink potentials.

Global Rock C-Sink guidelines for sustainable rock weathering

Link