Confusion on C1 Categories #80
Description
In last Scenarios Compass meeting, there was some confusion about the category naming that arose i.e.
definition of C1a/C1b in checks.py refers to
# C1b (1.5°C with low OS, lower than likely probability of >= 1.5 peak
# warming and < 1.5 end of century warming with 50%)
dfar6.meta.loc[
(dfar6.meta[Tp33Peak] <= c15_peak) & (dfar6.meta[c15_EOC] < 1.5),
["Category", "Category_name"],
] = ["C1b", "C1b: Below 1.5°C with low OS"]
# C1a (1.5°C more likely than not with no overshoot)
dfar6.meta.loc[
dfar6.meta[TmedPeak] < 1.5,
["Category", "Category_name"],
] = ["C1a", "C1a: Below 1.5°C with no OS"]
I think this came originally from SR15 and was implemented before what subsequently became more commonly known C1a/C1b categories in AR6 WG3 Table 2 of C1 with and without net-zero GHGs (which was introduced during SPM approval).
I think it would be prudent to change this to avoid further confusion:
- rename categories above to something like C1LOS and C1NOS.
- Alternatively, implement C1a/C1b taking into account net-zero GHGs or not. N.B. may not want to go down this route, as this can be loaded with assumptions, e.g. native or harmonized-infilled emissions, what threshold (0 or e.g. 0.1 Gt), etc etc.
Ultimately, a scenario can only have one Category, which is primarily the climate outcome, so I think the easiest and least controversial fix would be just do Option 1 above.
Thoughts? @jkikstra @danielhuppmann @znicholls