Role of international bunker emissions / global aggregates

[orichters]

Dear @IAMconsortium/common-definitions-emissions team,

I would be glad if you could decide about the treatment of international bunkers.

As far as I know, In the AR6 template, Emissions|* variables for BC, CO, CO2, NOx, OC, Sulfur and VOC had the international bunkers added only at the global level, leading to a situation that the sum over all regions did not match World results. In the NGFS project, we found out that the MESSAGE team also used this treatment for Final Energy|Gases and Primary Energy|Gas, while REMIND did it only for Emissions, and GCAM not at all. So there is definitely much room for confusion.

So I would be pleased if the variable description clarified how this should be treated. Thanks!

If I know that correctly, in NAVIGATE, the international bunkers were meant to be distributed to the regions, and I would propose to stick to that but make it explicit in the variable definition.

[danielhuppmann]

@volker-krey @strefler, please chime in here.

[strefler]

Yes, I think it makes sense to distribute the international bunkers (emissions and energy alike) to regions. If we don't do that, as Oliver noted the sum of regions will not equal the World total, and we still have emission and energy totals without bunkers if we need those values to compare to national inventories.

[orichters]

@volker-krey: An answer would be appreciated. We would like to "World = sum(regions)" for all variables in NGFS as well, and if we knew in the REMIND team that this is the future for the community template, that would make all our lives easier.