EASIER-F

Soil organic carbon (SOC) is one of the most important organic C pools on Earth with C turnover ranging from days to millennium. In Earth system models (ESMs), which are models aiming at simulating all the relevant aspects of the Earth system (climate, ocean circulation, greenhouse gases exchanges, etc.), simulations start from an equilibrium state assuming that the full system was at equilibrium before the simulations. But due to long SOC turnover, soil disturbances (e.g. land use change) that have taken place long time ago may still impact the SOC dynamics today. Thus, this equilibrium state assumption is not valid and therefore all current ESMs simulations are based on an incorrect conceptualization of the system. Moreover, in ESMs, the soil is still represented based on pools that are not measurable, making parameterization and evaluation of this key ESM component’s climate impact difficult. The big challenge of EASIER is to propose a new initialization procedure for soil in ESMs. To fulfil this aim, I need to i) develop a soil model using measurable pools included in an ESM that has contributed to IPCC assessment reports for the past two decades; ii) to carry out field measurements of these soil pools using Rock-Eval analysis, a technology initially developed in oil industry and which I previously helped adapt to soil science ; iii) answer basic questions on the stabilization mechanisms of SOC using a combined measurement of 14C and CO2 with different aggregate compositions; iv) run European-level simulations with this new non-soil-equilibrium ESM to study the climate-carbon feedbacks due to soil . EASIER presents a highly original approach that will propose several innovative solutions leading to numerous breakthroughs in the field of carbon/climate feedbacks.