Notes

NOTES

1. Global human-made emissions were estimated at 49.04 GtCO2e in 2015, according the

European Commission’s Emissions Database for Global Atmospheric Research (EDGAR), accessed May 21, 2021 (https://edgar.jrc.ec.europa.eu/country_profile). 2. Based on 2015 global GHG emissions reported in EDGAR. 3. Regulation has proven effective in tackling scope 3 emissions, for instance by tightening vehicle emission standards. 4. Based on 159 billion cubic meters of natural gas flared in 2019, 98 percent flare efficiency, and a global warming potential of methane of 30 on a 100-year horizon basis. Throughout this report, methane is assigned a global warming potential of 30 to ensure consistency with the IEA’s (2021b) key assumptions. 5. Methane emissions during flaring are included in the previously mentioned 462 MtCO2e emissions from flaring. 6. Estimates of flared volumes for 2020 and 2019 come from the Global Gas Flaring

Reduction Partnership (GGFR) website (https://www.worldbank.org/en/programs /gasflaringreduction#7). Estimates of methane emission volumes come from the IEA (2020b) and the IEA’s Methane Tracker Database (https://www.iea.org/articles/methane -tracker-database). 7. In gas fields, there is no or minimal flaring. Relatively few gas fields contain gas with significant volumes of heavier hydrocarbons that are extracted from the produced gas and sold. In many cases the lighter components, methane and ethane, are reinjected into the reservoir. In some cases, however, these components are flared. See Elvidge et al. (2018) and the World Bank’s Zero Routine Flaring by 2030 web page (https://www.worldbank .org/en/programs/zero-routine-flaring-by-2030#7). 8. The volume of gas flared in 2020 was equivalent to approximately 3.9 percent of the total gas produced globally. 9. World Bank’s Zero Routine Flaring by 2030 web page (https://www.worldbank.org/en /programs/zero-routine-flaring-by-2030). 10. IEA’sMethaneTrackerDatabase (https://www.iea.org/articles/methane-tracker-database).

Note that estimates of volume of gas vented are highly dependent on the gas density (kilogram per cubic meter) assumed. 11. The US Energy Information Agency, using 2012 data, estimates that 15 percent of associated gas production was flared or vented, 58 percent reinjected, and 27 percent used. 12. The calculation assumes a 40 percent conversion efficiency from gas to power. For medium- and large-scale power generation units, the conversion efficiency would be between 40 percent and 45 percent; small-scale units would likely show efficiencies between 30 percent and 35 percent. 13. The ideal measure of effectiveness of a country’s gas use is the ratio of gas used to gas produced; however, volumes of associated gas produced are rarely publicly available. 14. The Methane Guiding Principles best-practice guides can be accessed at https:// methaneguidingprinciples.org/best-practice-guides/. 15. This estimate is consistent with Saunois et al. (2016, 2020). 16. IEA’s Methane Tracker Database (https://www.iea.org/articles/methane-tracker-database). 17. The IEA compared its estimates to several other sources and found them to be generally in line (https://www.iea.org/articles/methane-tracker-database). 18. IEA’s Methane Tracker Database (https://www.iea.org/articles/methane-tracker-database). 19. IEA’s Methane Tracker Database (https://www.iea.org/articles/methane-tracker-database). 20. IEA’s Methane Tracker Database (https://www.iea.org/articles/methane-tracker-database). 21. Per the IEA (2021b), methane emissions from fossil fuel production and use fall from 115

Mt in 2020 (3.5 GtCO2eq) to 30 Mt in 2030 and 10 Mt in 2050 in the Net Zero Emissions scenario. About one-third of this decline results from an overall reduction in fossil fuel consumption, but the larger share comes from a huge increase in the deployment of emission reduction measures and technologies, which lead to the elimination of all technically avoidable methane emissions by 2030 (IEA 2020a). 22. Of the 197 countries that endorsed the Paris Agreement, 190 have formalized their commitment. A handful of high emitters have yet to formally join the Paris Agreement, including the Islamic Republic of Iran, Iraq, and Turkey. For details on the Paris Agreement, see the

United Nations Climate Change web page (https://unfccc.int/process-and-meetings /the-paris-agreement/the-paris-agreement).