flat10MIP: an emissions-driven experiment to diagnose the climate response to positive, zero and negative CO 2 emissions

作者：Benjamin M. Sanderson, Victor Brovkin, Rosie A. Fisher, D. Höhn, Tatiana Ilyina, Chris Jones, Torben Koenigk, Charles D. Koven, Hongmei Li, David M. Lawrence, Peter A. Lawrence, Spencer Liddicoat, Andrew H. MacDougall, Nadine Mengis, Zebedee Nicholls, Eleanor O’Rourke, Anastasia Romanou, Marit Sandstad, Jörg Schwinger, Roland Séférian, Lori T. Sentman, Isla R. Simpson, Chris Smith, Norman Julius Steinert, Abigail L. S. Swann, Jerry Tjiputra, Tilo Ziehn · 发表于：Geoscientific model development · 年份：2025 · DOI：10.5194/gmd-18-5699-2025 · 被引用次数：10 · 研究领域：Atmospheric and Environmental Gas Dynamics、Atmospheric chemistry and aerosols、Climate variability and models

Abstract. The proportionality between global mean temperature and cumulative emissions of CO2 predicted in Earth system models (ESMs) is the foundation of carbon budgeting frameworks. Deviations from this behavior could impact estimates of required net-zero timings and negative emissions requirements to meet the Paris Agreement climate targets. However, existing ESM diagnostic experiments do not allow for direct estimation of these deviations as a function of defined emissions pathways. Here, we perform a set of climate model diagnostic experiments for the assessment of transient climate response to cumulative CO2 emissions (TCRE), the Zero Emissions Commitment (ZEC), and climate reversibility metrics in an emissions-driven framework. The emissions-driven experiments provide consistent independent variables simplifying simulation, analysis and interpretation, with emissions rates more comparable to recent levels than existing protocols using model-specific compatible emissions from the CMIP DECK 1pctCO2 experiment, where emissions rates tend to increase during the experiment, such that at the time of CO2 doubling in year 70, emissions are much greater than present-day values. A base experiment, “esm-flat10”, has constant emissions of CO2 of 10 GtC per year (near-present-day values), and initial results show that the TCRE estimated in this experiment is about 0.1 K less than that obtained using 1pctCO2. A subset of ESMs exhibit land carbon sinks that saturate during this exper...