WP1: What is the comprehensive climate impact of specific carbon dioxide removal options?
We will extend previous work on forcing footprints of human activities to estimate climate forcing footprints of terrestrial Carbon Dioxid Removal (CDR) options as currently represented in policy-informing Integrated Assessment Models.
This project constitutes a novel compilation of information, that is currently emerging from the continued efforts in CDR research. But it goes beyond that: Here we will provide the fundamental knowledge that is needed to improve the representation of CDR measures in policy-informing scenario analysis.
WP2: Which are the most relevant processes in the Earth system to determine its response to a cessation of CO2 emissions?
In this WP, we will use the data from the Zero Emissions Commitment Model inter-comparison project (ZECMIP). For ZECMIP modelling groups were asked to perform simulations in which CO2 emissions are stopped. The application of the Systematic Correlation Matrix Evaluation tool (SCoMaE), that I developed during my PhD to the ensemble of ZECMIP, will enable us to provide process level insights into global mean and regionally resolved patterns of multi-model variability.
Accordingly, we can identify the key Earth system processes that drive uncertainty in zero CO2 emissions scenarios.
WP3: How does the Earth system react to all-forcing net-zero CO2 scenarios?
Contributions of human activities on how we reach net-zero CO2 emissions can vary quite strongly.
In this WP, we will use the newly released University of Victoria Earth system climate model (UVic ESCM version 2.10) including the atmospheric chemistry module, which allows us to directly force the model with multi-gas emissions data from a variety of net-zero CO2 scenarios from Rogelj et al., 2019.
This study will be the first to use an Earth system model of intermediate complexity to study the temperature response to all-forcing net-zero-2050 scenarios. It will provide crucial information about both, the carbon cycle and climate dynamics, of such scenarios. Processes that are only represented in an idealised way in reduced complexity climate models. This study hence builds an important bridge between the Earth system modelling and the integrated assessment model communities.
In WP4, we will combine the new findings about CDR forcing footprints, and the Earth systems response to net-zero CO2 (multi-gas forcing) scenarios, to identify potential temperature stabilisation scenarios. We will then perform an Earth system uncertainty assessment based on the most relevant processes identified under zero CO2 emission scenarios in WP2.
Finally, statistical uncertainty analyses will allow us to provide fractions of variability in temperature stabilisation scenarios.
The time dependent fractions of variability, resolved down to single Earth system processes, will allow us to point to the most relevant processes in temperature stabilisation scenarios in the near term, but also by the end of the century.
Improving the observational constraints for those processes would increase our confidence in projecting the future temperature response once we have minimised our influence on the climate system.
In addition, I will also be able to estimate the most likely future CO2 emission scenarios, that would lead to temperature stabilisation.