This study aims to create insight in how Integrated Assessment Models (IAMs) perform in describing the climate forcing by non-CO2 gases and aerosols. The simple climate models (SCMs) included in IAMs have been run with the same prescribed anthropogenic emission pathways and compared to analyses with complex earth system models (ESMs) in terms of concentration and radiative forcing levels. In our comparison, particular attention was given to the short-lived forcers' climate effects. In general, SCMs show forcing levels within the expert model ranges. However, the more simple SCMs seem to underestimate forcing differences between baseline and mitigation scenarios because of omission of ozone, black carbon and/or indirect methane forcing effects. Above all, results also show that among IAMs there is a significant spread (0.74 W/m(2) in 2100) in non-CO2 forcing projections for a 2.6 W/m(2) mitigation scenario, mainly due to uncertainties in the indirect effects of aerosols. This has large implications for determining optimal mitigation strategies among IAMs with regard to required CO2 forcing targets and policy costs.
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机译：这项研究旨在就综合评估模型（IAM）在描述非CO2气体和气溶胶对气候的强迫作用方面表现出深刻见解。 IAM中包含的简单气候模型（SCM）已使用相同的规定的人为排放途径运行，并与浓度和辐射强迫水平方面的复杂地球系统模型（ESM）进行了比较。在我们的比较中，特别关注了短命的部队对气候的影响。通常，SCM显示强制级别在专家模型范围内。但是，由于省略了臭氧，黑碳和/或间接强迫甲烷作用，更简单的供应链管理似乎低估了基准情景和缓解情景之间的强迫差异。最重要的是，结果还表明，在2.6 W / m（2）缓解情景中，非CO2强迫预测中的IAM之间存在显着差异（2100年为0.74 W / m（2）），这主要是由于间接的不确定性气雾剂的影响。这对于确定IAM中有关所需的CO2强制目标和政策成本的最佳缓解策略具有重大意义。
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