Add CEDS variable-aggregation mapping

[danielhuppmann]

This PR adds a mapping from the standard emissions variable tree to CEDS categories, per some discussion with @jkikstra

One complicated issue is the handling of transportation-emissions, where domestic aviation is part of "Emissions|*|Energy|Demand|Transportation" in the IAMC convention but part of "Aircraft" in CEDS.

@jkikstra suggested simply doing "Tranportation minus Domestic Aviation", but including computation-instructions goes against the spirit of a well-readable mapping.

Instead, I added two variables

• Emissions|CO2|Energy|Demand|Transportation|Road
• Emissions|CO2|Energy|Demand|Transportation|Other

that are not yet included in the variable template.

To be discussed further bilaterally.

FIY @IAMconsortium/common-definitions-emissions

[jkikstra]

Some comments:

1. is this just as a starting point that it is specific to CO2? We'll eventually want to do more species. At least the 10 species that are in CEDS and GFED, which is where the variable mapping will be happening. Later we may also
2. The four burning variables are from GFED, not CEDS.
3. The agriculture CO2 will come from Global Carbon Budget, CEDS does not do Agriculture CO2.
4. Other emissions species (e.g., particular F-Gases) would also be nice to add them, but they will so far only be used as 'Total' (i.e., not by sector) and their sources will be varied (e.g. from WMO); not fully finalised yet.

[danielhuppmann]

Yes, this is just a starting point and will be extended to cover all emissions. And we can add total-emissions variables as well later.

Renamed the variables per comments 2 and 3.

[robertpietzcker]

Hi Daniel,
maybe I am overlooking something obvious, but I am currently wondering what would be reported under "Other" if "Domestic Aviation" has a separate variable?

[danielhuppmann]

what would be reported under "Other" if "Domestic Aviation" has a separate variable?

This is a fix for now while I develop the CEDS-rename-aggregation tool, because some scenarios only report some of the transportation detail, so simple aggregation doesn't work. So I intend to do something like

0. Compute "Transportation|Other" as "Transportation" minus "Transportation|Domestic Aviation"
1. Use the mapping above to compute the CEDS variables
2. Drop the "Transportation|Other" variable from the scenario

[robertpietzcker]

thanks for the explanation - sounds good!