Institute for Sustainability

Urban soils capture carbon

Urban soils for rapid carbon capture

While many of the world’s cities are working towards sustainability, they are the largest source of greenhouse gas emissions in the world, accounting for 70% of humans’ carbon footprint.

To counterbalance the impact of urban environments on the climate, Prof David Manning and Dr Elisa Lopez-Capel are investigating how artificial urban soils can help.  

It is well-known that making concrete is not sustainable as it is highly energy intensive emitting large amounts of carbon dioxide. What isn’t widely known is that the minerals in concrete that enter the soil after a building is demolished react with the CO2 in the atmosphere, acting as a rapid carbon sink.   

‘Minerals in soils are dynamic reactants. This means any soil rich in calcium or magnesium from waste materials such as concrete or metal slag is also a potential carbon sink. We are interested in working with government and industry to apply carbon capture solutions for sustainability using urban soils’, says Prof David Manning. 

Soil engineering provides effective solutions for offsetting carbon emissions. This was found at the Science Central site in Newcastle, UK. The soil there contains building fragments left from the demolition of the former Newcastle Brewery building. Soil with portlandite from concrete and calcite suck up 85 tonnes of CO2 per hectare, removing even more carbon than growing woodlands on agricultural land. This is the first time changes in soil inorganic carbon have been measured in urban soils over time.

‘Unused brownfield sites in cities can be used for urban carbon capture even if they are only left vacant for five years, just 12 acres could serve as an adequate sink for storing carbon,’ says Dr Elisa Lopez.

If less than one percent of urban soils in the UK are managed similar to the Science Central site it could remove one mega tonne of CO2 annually. This could help countries throughout the world to meet their targets for greenhouse gas reductions using urban soils.

Find out more about this research on the SUCCESS project's website.

Selected Publications:

Urban soil carbon capture at Science Central.