CMIP6 Simulations With the CMCC Earth System Model (CMCC‐ESM2)

• Published in: Journal of advances in modeling earth systems 2022-03, Vol.14 (3), p.n/a
• Main Authors: Lovato, T., Peano, D., Butenschön, M., Materia, S., Iovino, D., Scoccimarro, E., Fogli, P. G., Cherchi, A., Bellucci, A., Gualdi, S., Masina, S., Navarra, A.
• Format: Article
• Language: English
• Subjects: Atmosphere; Benthos; Biogeochemistry; Carbon; Carbon cycle; Carbon sinks; Climate; Climate change; climate changes; Climate sensitivity; CMIP6; coupled climate‐carbon cycles; Decomposition; Earth; Earth System Model; General circulation models; global biogeochemical cycles; Global warming; Intercomparison; Marine ecosystems; Modelling; Nitrogen; Nitrogen cycle; Oxygen; Primary production; Respiration; Simulation; Storage; Trophic levels; Vegetation
• ISSN: 1942-2466; 1942-2466
• DOI: 10.1029/2021MS002814

This article introduces the second generation CMCC Earth System Model (CMCC‐ESM2) that extends a number of marine and terrestrial biogeochemical processes with respect to its CMIP5 predecessor. In particular, land biogeochemistry was extended to a wider set of carbon pools and plant functional types, along with a prognostic representation of the nitrogen cycle. The marine ecosystem representation was reshaped toward an intermediate complexity of lower trophic level interactions, including an interactive benthic compartment and a new formulation of heterotrophic bacterial population. Details are provided on the model setup and implementation for the different experiments performed as contribution to the sixth phase of the Coupled Model Intercomparison Project. CMCC‐ESM2 shows an equilibrium climate sensitivity of 3.57°C and a transient climate response of 1.97°C which are close to the CMIP5 and CMIP6 multi‐model averages. The evaluation of the coupled climate‐carbon response in the historical period against available observational datasets show a consistent representation of both physical and biogeochemical quantities. However, the land carbon sink is found to be weaker than the current global carbon estimates and the simulated marine primary production is slightly below the satellite‐based average over recent decades. Future projections coherently show a prominent global warming over the northern hemisphere with intensified precipitations at high latitudes. The expected ranges of variability for oceanic pH and oxygen, as well as land carbon and nitrogen soil storage, compare favorably with those assessed from other CMIP6 models. Plain Language Summary Earth System Models integrate our knowledge on the underlying physical and biogeochemical mechanisms that drive or influence the global climate and the biosphere over the land and in the ocean. These models are used to provide realistic estimates of climate variability and its response to perturbations in the chemical constituents of the atmosphere and modifications of the terrestrial surface. This work describes the science at the base of the second generation Earth System Model developed at the Euro‐Mediterranean Centre on Climate Change and the major results obtained from the simulation of historical (from the pre‐industrial period until present) and different future scenarios up to 2100 in the context of the sixth Coupled Model Intercomparison Project. The model provides a solid representation of the pres