RESET

Project goals

Silicate weathering naturally but slowly removes CO₂ from the atmosphere by reactions that convert CO₂ to dissolved aqueous bicarbonate ions that can be stored in the ocean for millennia, or into carbonate minerals that are stored essentially permanently. Enhanced Silicate Weathering (ESW) promises to achieve large volume carbon dioxide removal (CDR) with millennium-scale storage and at competitive cost by distributing finely ground reactive (ultra)mafic rock, e.g. basalts, on agricultural soils. Models predict that ESW can make a substantial contribution to Germany’s CDR targets, but they lack empirical ground-truthing. A central issue is that the timescales of ecosystem response are longer than most experimental setups, meaning we lack a proper demonstration ESW works and a strategy for quantifying and certifying carbon drawdown. We also don’t know the long-term impact on soil-plant systems – in particular organic carbon dynamics – nor whether the short-term weathering rates derived from lab experiments can be sustained over longer timescales. Finally, we don’t know the feasible limits of ESW because optimal scaling and deployment strategies that consider both geochemical and socio-economic constraints have not been developed.

The RESET project (Developing Roadmaps to Scalable Carbon Dioxide Removal by Enhanced Silicate Weathering) aims to tackle these knowledge gaps. Specifically, we will explore novel applications of isotope geochemical proxies and we will investigate the long-term efficacy and impacts of ESW by exploiting ‘unintended’ experiments on German agricultural land where rock powder has historically been applied as fertiliser for decades. We will use both the isotope geochemical tools and state-of-the-art organic geochemistry approaches to assess the impact of ESW of soil organic carbon. These results will be used to guide a geochemical prioritisation for effective implementation that complements a socio-economic analysis of the causal relationships and systemic impacts, drivers and barriers of ESW. Ultimately, we aim to develop a roadmap for the large-scale deployment of ESW for durable CO₂ removal.