Error in batch_SSP_SPA23.xml - Missing negative_emissions_budget_SSP3.xml in GCAM v7.1

[choiHenry]

Hello,

I am a PhD candidate in Seoul National University, Korea.

Thank you for creating and maintaining such a wonderful model. I appreciate all the hard work that has gone into this project.

I have found a small error in the batch_SSP_SPA23.xml file. It appears that the negative_emissions_budget_SSP3.xml file is missing in GCAM v7.1. I noticed that this file exists in GCAM v7.0, where negative emissions budget files are provided for SSP1-SSP5.

The relevant section in the batch_SSP_SPA23.xml file can be modified as follows:

<Value name = "bio_neg_emiss_budget">../input/gcamdata/xml/negative_emissions_budget.xml</Value>

This change should address the issue.

Thanks for taking the time to read this. I look forward to any updates or guidance you might provide.

Best regards,

Henry.

[realxinzhao]

Thanks, Henry! Good catch!

You are right. When GCAM-macro was merged, we restructured/updated negative_emissions_budget across all SSPs to allow using endogenous GDP and simplify those files. But we missed this configuration update for SSP3 as you pointed out (even back in GCAMv7 I think). We will get this one corrected later.

However, please also note that SSP3-RCP2p6 is indeed a scenario that was considered as not solvable (too stringent a target given SSP3). So it has not been a default validation scenario in our core model proposals (CMPs): https://github.com/JGCRI/gcam-doc/tree/gh-pages/cmp

Thanks, Xin

[choiHenry]

Thank you very much for your kind response, Xin.

I tried to find a path for a temperature target 1p5 with SSP3, but the model did not solve.

(Interestingly, the model successfully solved for SSP1, SSP2, SSP4, and SSP5.)

I'd be frustrated without your mention of SSP3-RCP2p6.

Best regards,

Henry.