The 2015 Paris Climate Agreement brought nations together to mitigate anthropogenic climate change, with the aim to keep global temperature rise below 2°C above pre-industrial levels. Artificially enhanced weathering of basalt, driven by intensified geochemical and biological processes that naturally promote the absorption of CO2, is considered as a potentially significant negative emissions technology. However, the impact of climate change and elevated greenhouse conditions on the rate and processes of basalt weathering and the role of plants in mediating this process are unconstrained. This Marie Skłodowska Curie Individual Fellowship aims to address this uncertainty by a multidisciplinary study on silicate weathering of basalts during the Paleocene climatic greenhouse world, using state-of-the-art botanical and geochemical proxies, tools and methods in the PALEOCARBON project. The project will focus on three main objectives: (1) Quantifying elevated Paleocene pCO2, temperature and precipitation levels using fossil leaves; (2) Constraining processes & intensity of silicate weathering and carbon drawdown potential in Paleocene basalts; (3) Quantifying elemental uptake of plants grown in high pCO2 laboratory conditions, to constrain the role of plant in mediating weathering processes. The PALEOCARBON project has the ultimate aim to constrain the fundamental end-member parameters that control the efficiency of (artificially) enhanced weathering as a potential negative carbon emissions technology. The findings suggest that (1) enhanced silicate weathering under elevated atmospheric CO2 levels may act as an important mechanism in stabilising Earth’s atmospheric CO2 levels during past super-greenhouse events as well as during future climate change; (2) plant mediation may play an important role in enhancing silicate weathering rate; (3) the impact of the addition of basaltic materials on plant growth is not necessarily positive, as it may not be a simple nutrient addition or soil remediation effect.
