emIAM v1.0: an emulator for Integrated Assessment Models using marginal abatement cost curves
Abstract. We developed an emulator for Integrated Assessment Models (emIAM) based on a marginal abatement cost (MAC) curve approach. Using the output of IAMs in the ENGAGE Scenario Explorer and the GET model, we derived a large set of MAC curves: ten IAMs; global and eleven regions; three gases CO2, CH4, and N2O; eight portfolios of available mitigation technologies; and two emission sources. We tested the performance of emIAM by coupling it with a simple climate model ACC2. We found that the optimizing climate-economy model emIAM-ACC2 adequately reproduced a majority of original IAM emission outcomes under similar conditions, allowing systematic explorations of IAMs with small computational resources. emIAM can expand the capability of simple climate models as a tool to calculate cost-effective pathways linked directly to a temperature target.
Weiwei Xiong et al.
Status: open (until 29 Apr 2023)
- RC1: 'Comment on egusphere-2022-1508', Anonymous Referee #1, 20 Mar 2023 reply
- RC2: 'Comment on egusphere-2022-1508', Yang Ou, 30 Mar 2023 reply
Weiwei Xiong et al.
Data for "emIAM v1.0: an emulator for Integrated Assessment Models using marginal abatement cost curves" https://doi.org/10.5281/zenodo.7478234
Weiwei Xiong et al.
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This study estimated a large set of marginal abatement cost (MAC) curves based on the output of IAMs in the ENGAGE Scenario Explorer and the GET model. The MAC curves were then applied to the emulator for Integrated Assessment Models (emIAM) and coupled to a simple climate model, ACC2. The test results showed that emIAM was able to reproduce the original IAM emission outcomes under similar conditions. The topic provided rich information about MAC curves under various IAMs, as well as different regions evaluated in the manuscript. While I agree with the authors that the analysis provided by the authors is certainly of general interest to climate-economic model developers and climate-focused researchers, I unfortunately cannot recommend publication of the manuscript in its present form. Here are my concerns:
First, the authors reviewed a range of existing literature about the categories of MAC curves and different MAC curves estimated under various backgrounds. However, the results and analysis generally focused on the outcome of this study. I recommend adding a comparison between the estimated MAC curves in this study and those presented in existing studies, including differences in function forms, appropriate interpretation of parameters, and other major differences compared to existing estimates.
Second, the ENGAGE Scenario dataset includes a wide range of outputs from various IAMs and regions. I am not quite sure about the reasons why the output of a separate GET model was also used for estimating the MAC curves. An explanation of the necessity of adding the output of the GET model is needed for readers to understand the framework of this study more clearly.
Third, the manuscript mentions that the emIAM-ACC2 model minimized total abatement costs to obtain possible emission pathways for reproducing the outcomes from other IAMs. More information about how this process works is needed, including the necessary equations and the objective function for minimizing.
Fourth, this study provided many figures (some of which are similar) to present the estimations of the MAC curves and the emulating results, especially in the Supplement. While these figures provide visual information to present relevant results, there are too many figures stacked together, making it difficult for readers to find the information they need. An appropriate way to manage these figures, such as indexing them using tables or other means of relevance, should be added.