Greenhouse Gas Removal via Enhanced Rock Weathering (GGREW)

To limit the increase in global temperature to less than 2 °C, “negative emissions”, or the active removal of carbon dioxide from the atmosphere, are required. Weathering, the chemical breakdown (dissolution) of rocks at the Earth’s surface, is a natural process that converts atmospheric carbon dioxide into carbonate minerals or hydrogen carbonate and carbonate ions (“alkalinity”). If the weathering process can be speeded up, or enhanced, then levels of atmospheric carbon dioxide would fall.

Mining of precious commodities, such as diamonds and gold, provides a continuous supply of freshly ground up rock material which, under the right conditions, could be easily weathered, removing atmospheric CO2 in the process.

Our project aims to provide critical knowledge to answer the following questions:
• Are rocks left over from extracting precious metals suitable for capturing carbon dioxide on human timescales?
• Are there low-cost engineering solutions that can be used to accelerate the weathering process?
• How much carbon dioxide could potentially be captured?

We are addressing these questions through identification of the most easily weatherable mine waste materials, the testing of physical, chemical and biological methods for speeding up weathering kinetics, and an investigation into the availability of (suitable) rock materials at mine sites on a national and global scale.