IN BRIEF: EMISSIONS OF INDIRECT GREENHOUSE GASES HAVE TO BE REPORTED TO UNFCCC
The EU publishes annually its official inventory of greenhouse gas emissions as required under the UNFCCC. As part of this submission, emissions of CO, NOx, NMVOC (non-methane volatile organic chemicals, which includes hydrocarbons) and SO2 have to be reported to the UNFCCC Secretariat because they influence climate change indirectly: CO, NOx and NMVOC are precursor substances for ozone which itself is a greenhouse gas.
The indirect warming effects of non-methane hydrocarbons such as propane and butane are included in their GWPs listed in the F-Gas Regulation 517/2014 Annex IV, which are IPPC AR4 GWP values.
For more information see the EFCTC newsletter article from 2019 September “In brief: direct and indirect GWPs for very low GWP substances”