Major Updates to Hector, a Simple Climate Model
Improvements to Hector’s terrestrial carbon cycle include the addition of permafrost dynamics and incorporating the effect of land use and land cover change emissions on Hector’s terrestrial carbon pools.
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Hector, which is a member of the class of models referred to as Simple Climate Models (SCMs), represents climate processes on a global annual scale. Since Hector was first documented in a 2015 manuscript, a number of changes have been made to the model. Major new features include permafrost thaw, a reworked energy balance component, and updated parameter values. Ultimately, these developments have improved Hector’s ability to reproduce the historical global temperature and carbon dioxide (CO2) concentrations. Additionally, Hector’s modern decadal (2014-2024) average sea surface temperature and ocean pH are consistent with recent observations.
SCMs are important tools with a wide range of applications. They are computationally efficient sources of climate projections and can be used to produce large ensembles of results and explore uncertainties in the climate and carbon cycle. As a stand-alone model, Hector can be used to conduct climate and carbon cycle research. Hector also serves as the climate component of the Global Change Analysis Model (GCAM), which allows GCAM to be used to research Human-Earth system interactions. These recent scientific advancements pave the way for broader possibilities for Hector and its application.
Researchers have documented the advancements made to Hector, a simple climate model, since its initial release in 2015. Some of the more notable changes affect how radiative forcing is calculated and Hector’s terrestrial carbon cycle. The two most important changes to Hector’s terrestrial carbon cycle include the addition of permafrost dynamics and incorporating the effect of land use and land cover change emissions on Hector’s terrestrial carbon pools. These changes increased both the complexity and comprehensiveness of Hector’s terrestrial carbon cycle and ultimately improved the model’s performance. To assess the model's performance, researchers compared Hector's results with historical observations of temperature and atmospheric CO2 concentrations. Additionally, the researchers demonstrated that Hector's temperature results from idealized experiments and multiforcing scenarios fall within the spread of CMIP6 Earth System Models. Key climate metrics, such as the transient climate response to cumulative CO2 emissions and future warming, fall within the ranges reported in the Intergovernmental Panel on Climate Change 6th Assessment Report.