Natural analogues and system-scale modeling of marine enhanced silicate weathering (DEHEAT).

Global climate change is one of the biggest global challenges of the 21st century and urgently requires ambitious, transformative, and collective action to limit global warming. This can be achieved either by preventing emissions of carbon dioxide (CO2) and other greenhouse gases to the atmosphere ("conventional mitigation") or by actively removing CO2 from the atmosphere ("negative emissions"). However, to reach the Paris climate goal and limit global warming below 2°C, we will need to rely on negative emission technologies (NETs, also called Carbon Dioxide Removal technologies, CDR). A promising NET approach is Enhanced Silicate Weathering (ESW). ESW makes use of the natural weathering reaction, whereby silicate dissolution consumes atmospheric CO2. The core idea of ESW is to distribute silicate minerals in environments that are characterized by high weathering rates, thus enhancing the uptake of atmospheric CO2 by increasing the alkalinity of the ocean. Here, we aim at examining, for the first time, the feasibility of ESW under marine conditions, taking advantage of the coastal ocean as a large-scale, natural biogeochemical reactor. One important research question pertains to the efficiency of marine ESW in stimulating oceanic CO2 uptake by increasing alkalinity in the coastal ocean. A second critical issue concerns the potential side-effects (both positive and negative) on marine ecosystems, including the enhanced availability of silicate and the potential release of iron and trace elements. To address these critical knowledge gaps, we will apply an innovative, fully integrated model-data approach combining RV Belgica field campaigns with state-of-the-art numerical models. Specifically, we will: (I) quantify the sediment geochemistry and mineralogy of natural analogues for ESW (II) develop and apply process-based local diagenetic models to quantify benthic weathering rates and benthic-pelagic exchange fluxes (III) design a large-scale virtual field trial to assess the efficiency and full environmental impact of applying ESW as NET on the North Sea scale. Results will not only provide important quantitative information on ESW in the marine environment but also the first system-scale assessment of marine ESW as a NET. The scenario-based virtual analysis will further augment the direct value of the proposed unique RV Belgica field observations. Together, they will a major step towards science-based decision-making on the application of NETs and will put Belgium firmly at the forefront of marine coastal ESW research.

Keywords:CARBON SEQUESTRATION, OCEANOGRAPHY, CLIMATE MITIGATION

Disciplines:Chemical oceanography

Project type:Collaboration project