Integrated assessment model diagnostics: key indicators and model evolution

Integrated assessment models (IAMs) form a prime tool in informing climate mitigation strategies. Diagnostic indicators that allow to compare these models can help to describe and explain differences in model projections. This also increases transparency and comparability. Earlier, the IAM community has developed an approach to diagnose models (Kriegler et al., 2015). Here we build on this, by proposing a selected set of well-defined indicators as a community standard, similar to metrics used for other modeling communities such as climate models. These indicators are the relative abatement index (RAI), emission reduction type index (ERT), inertia timescale (IT), fossil fuel reduction (FFR), transformation index (TI) and cost per abatement value (CAV). We apply the approach to 17 IAMs, including both older version as well as their latest versions, as applied in the IPCC 6th Assessment Report (AR6). The study shows that the approach can be easily applied and allows for comparison of model versions in time. The indicators and their trends can often be explained in terms of model characteristics and changes. We show that together, the set of six indicators can provide an useful indication of the main traits of the model and can roughly indicate the general model behavior. The results also show that there is often a considerable spread across the models. Interestingly, the diagnostic values often change for different model versions, but there does not seem to be a distinct trend.

HARMSEN J.H. Mathijs;  KRIEGLER Elmar;  VAN VUUREN Detlef;  VAN DER WIJST Kaj-Ivar;  LUDERER Gunnar;  CUI Ryna;  DESSENS Olivier;  DROUET Laurent;  EMMERLING Johannes;  MORRIS Jennifer Faye;  FOSSE Florian;  FRAGKIADAKIS Dimitris;  FRAGKIADAKIS Kostas;  FRAGKOS P.;  FRICKO Oliver;  FUJIMORI Shinichiro;  GERNAAT David;  GUIVARCH Celine;  IYER Gokul;  KARKATSOULIS P;  KEPPO Ilkka;  KERAMIDAS Kimon;  KOBERLE Alex;  KOLP Peter;  KREY Volker;  KRÜGER Christoph;  LEBLANC Florian;  MITTAL Shivika;  PALTSEV Sergey;  ROCHEDO Pedro;  VAN RUIJVEN Bas;  SANDS Ronald D;  SANO Fuminori;  STREFLER Jessica;  VASQUEZ ARROYO Eveline;  WADA Kenichi;  ZAKERI Behnam; 

2021-05-21

IOP PUBLISHING LTD

JRC123454

1748-9326 (online),   

https://publications.jrc.ec.europa.eu/repository/handle/JRC123454,   

10.1088/1748-9326/abf964 (online),