outputs_emissions.md

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Description of Outputs

Name	Resolution	Unit	Query	XML Tag
Emissions1,2	Technology, Region3, and Year	Various4	nonCO2 emissions by tech	emissions
Land use change emissions	By GLU and land type	MtC / year	LUC emissions by region	land-use-change-emission
Change in above ground carbon	By GLU and land type	MtC / year		above-land-use-change-emission
Change in below ground carbon	By GLU and land type	MtC / year		below-land-use-change-emission
CO2 Sequestration6	Technology, Region3, and Year	MtC / year	CO2 sequestration by tech	emissions-sequestered

Outputs are specified in the `startVisitGHG`^{[5](#table_footnote)} and `startVisitCarbonCalc` methods of [xml_db_outputter.cpp](https://github.com/JGCRI/gcam-core/blob/master/cvs/objects/reporting/source/xml_db_outputter.cpp). 1: While the query is called "nonCO2 emissions", it also includes CO₂ emissions. A full list of gases included in GCAM is provided on the emissions page.
2: There is a long list of standard queries that report emissions outputs. The "nonCO2 emissions by tech" query listed above will report all emissions except for land use change CO₂ at the technology level. The other queries filter or aggregate those outputs. For example, the "CO2 emissions by region" query aggregates emissions to the region level for fossil fuel and industrial CO₂ only.
3: Emissions are reported at the regional resolution of the sector. See Regional Resolution
4: Units vary. CO₂ emissions are reported in MtC/yr. Fluorinated gas emissions are reported in Gg of the specific gas per year. All other emissions are reported in Tg of the specific gas per year (e.g., CH₄ emissions are reported in TgCH₄ / yr).
5: While the method is called startVisitGHG, it includes non-GHG emissions. However, land use change CO₂ emissions are not included in this method.
6: There are two emissions sequestration queries. The "CO2 sequestration by tech" query listed above will return CO₂ sequestration by technology, while "CO2 sequestration by sector" aggregates this to the sector level.