Research team

Ecosystem Management

Quantitative modelling of negative emissions through coastal enhanced silicate weathering. 01/11/2020 - 31/10/2022

Abstract

The societal challenge of limiting global warming to <2°C by 2100 cannot be achieved by reducing fossil fuel emissions alone (i.e. traditional mitigation), but requires that CO2 is actively captured from the atmosphere via negative emission technologies (NETs). Enhanced silicate weathering (ESW) is a promising candidate NET that uses the natural process of silicate weathering for the removal of CO2 from the atmosphere. By deliberately introducing fast-weathering silicate minerals into the coastal zone, one could create a coastal CO2 sink. A principal advantage of ESW over other NETs is that it counteracts ocean acidification and that it can be directly integrated into existing coastal management programs with existing (dredging) technology. Whilst the geochemical basis is firmly established and ESW has been proven to work in laboratory conditions, real life applications are hampered by uncertainties regarding CO2 sequestration rates and possible trace metal release. In this project, we will develop a quantitative biogeochemical sediment model that describes the dissolution of silicate minerals in marine sediments during ESW applications. The model will be validated by data from the international ESW mesocosm facility recently established in Oostende. From the model two critical tools will be derived, that will predict CO2 sequestration rates and trace metal release during real life ESW applications.

Researcher(s)

Research team(s)

Enhanced silicate weathering as CO2 removal strategy in coastal environments. 01/10/2019 - 30/09/2022

Abstract

To reach the Paris climate goals, conventional CO2 mitigation alone will not be sufficient, and large-scale deployment of negative emission technologies (NET) will be needed to extract CO2 back from the atmosphere. At present however, the feasibility, efficiency and environmental impact of currently proposed NETs is poorly constrained. This project will quantitatively investigate these issues for enhanced silicate weathering (ESW) in coastal environments, which is a newly proposed NET. The principle behind ESW is that the weathering of silicates releases alkalinity, which increases the CO2 uptake capacity of the ocean. To get a quantitative and mechanistic understanding of ESW under realistic conditions we will combine experimental work, field sampling and modelling efforts. In a large mesocosm facility, we will investigate the rate of olivine weathering, the effect on local geochemistry, the CO2 sequestration efficiency and the possible release of harmful trace metals (nickel, chromium). To examine effects on a longer timescale, we will perform a detailed geochemical assessment of two specific field sites, which have natural olivine weathering. All results will be analyzed using a comprehensive numeric modelling environment to fully unravel the connection between ESW and other biogeochemical processes. The results of this project will provide a first quantitative insight into the potential of coastal ESW as a negative emission technology.

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Research team(s)