Physical inconsistencies in the representation of the ocean heat-carbon nexus in simple climate models

Séférian, R., Bossy, T., Gasser, T. ORCID: https://orcid.org/0000-0003-4882-2647, Nicholls, Z. ORCID: https://orcid.org/0000-0002-4767-2723, Dorheim, K., Su, X., Tsutsui, J., & Santana-Falcón, Y. (2024). Physical inconsistencies in the representation of the ocean heat-carbon nexus in simple climate models. Communications Earth & Environment 5 (1) e591. 10.1038/s43247-024-01464-x.

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Abstract

The Ocean Heat-Carbon Nexus, linking ocean heat and carbon uptake, is crucial for understanding climate responses to cumulative carbon dioxide (CO2) emissions and to net zero CO2 emissions. It results from a suite of processes involving the exchange of heat and carbon across the sea-air interface as well as their storage below the mixed layer and redistribution by the ocean large-scale circulation. The Ocean Heat and Carbon Nexus is assumed to be consistently represented across two modelling platforms used in the latest IPCC assessments: the Earth System Models (ESMs) and the Simple Climate Models (SCMs). However, our research shows significant deficiencies in state-of-the-art SCMs in replicating the ocean heat-carbon nexus of ESMs due to a crude treatment of the ocean thermal and carbon cycle coupling. With one SCM, we show that a more realistic heat-to-carbon uptake ratio exacerbates the projected warming by 0.1 °C in low overshoot scenarios and up to 0.2 °C in high overshoot scenarios. It is therefore critical to explore how SCMs’ physical inconsistencies, such as the representation of the ocean heat-carbon nexus, can affect future warming projections used in climate assessments, not just by SCMs in Working Group 3 but also by ESMs in Working Group 1 via SCM-driven emission-to-concentration translation.

Item Type:	Article
Research Programs:	Advancing Systems Analysis (ASA) Advancing Systems Analysis (ASA) > Exploratory Modeling of Human-natural Systems (EM) Energy, Climate, and Environment (ECE) Energy, Climate, and Environment (ECE) > Integrated Assessment and Climate Change (IACC)
Depositing User:	Luke Kirwan
Date Deposited:	17 Jun 2024 07:42
Last Modified:	09 Sep 2024 12:38
URI:	https://pure.iiasa.ac.at/19814

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