# Methane Emission Estimates by the Global High-Resolution Inverse Model Using National Inventories
## 2 Materials and Methods
### Adjusting Prior Anthropogenic Emissions to National Reports  
EDGAR is a widely used, gridded emission inventory, and the UNFCCC reports only include the total annual emissions for each country. Annex I countries submit complete inventories of GHG emission sources and sinks from the base year (1990), and other countries are encouraged to submit their GHG inventories as part of their National Communications and Biennial Update Reports (BUR). To date, 150 countries have submitted one or more national communications with a summary of the GHG inventory. We compared the total CH\({}_{4}\) emissions with land use, land-use change, and forestry (LULUCF) sectors in UNFCCC reports (units: Gg) with the latest EDGAR v4.3.2 emission inventory which extended the emissions to 2012. The top fifteen emitting countries based on the EDGAR estimate for 2012 and other countries, including Germany, France, the United Kingdom, and Japan, were selected to adjust the inventory according to the UNFCCC reports. The countries selected are shown in Table 1, and these nineteen countries emit 66% of the total global methane emissions according to the values estimated by EDGAR v4.3.2 for the year 2012.  
The new gridded emission inventory based on the UNFCCC reports was produced by scaling the annual total value to the EDGAR estimation using Equation (2):  
\[E_{\text{UNFCCC}}(t)=E_{\text{EDGAR}\text{v4.3.2}}(t)\times\frac{1}{n}\sum_{k=1 }^{n}\left(\frac{E_{\text{UNFCCC}}(i)}{E_{\text{EDGAR}\text{v4.3.2}}(i)}\right) \tag{2}\]  
where \(t\) is the year (2010, 2011, or 2012); \(n\) is the number of reports to the UNFCCC by the top emitting countries listed in Table 1; and \(i\) is the recent four reporting years, from 2009 to 2012.  
For the remaining countries, \(E_{\text{UNFCCC}}(t)=E_{\text{EDGAR}\text{v4.3.2}}(t)\).  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Country** & **China** & **India** & **United** & **Brazil** & **Russian** & **Indonesia** & **Nigeria** & **Pakistan** & **Iran** & **Mexico** \\
**Name** & **China** & **India** & **States** & **Brazil** & **Federation** & **Indonesia** & **Nigeria** & **Pakistan** & **Iran** & **Mexico** \\ \hline EDGAR (Gg) & 66,297 & 32,582 & 25,770 & 19,212 & 17,441 & 12,027 & 7252 & 7213 & 6528 & 5201 \\ UNFCCC (Gg) & 55,914 & 19,776 (2010) & 27,099 & 16,808 & 33,894 & 11,257 & 4207 & 2890 & 3606 & 4558 \\ \hline
**Country** & **Australia** & **Thailand** & **Banglades** & **Canada** & **Argentina** & **Germany** & **France** & **United Kingdom** & **Japan** & \\ \hline EDGAR (Gg) & 4987 & 4893 & 4808 & 4679 & 4562 & 2768 & 2651 & 2624 & 1850 & \\ UNFCCC (Gg) & 4550 & 3171 & 1191 (1994) & 3939 & 3900 & 2340 & 2420 & 2424 & 1317 & \\ \hline \hline \end{tabular}
\end{table}
Table 1: The selected countries with high emissions and their methane emissions estimated by the Emissions Database for Global Atmospheric Research (EDGAR) v4.3.2 in 2012 and the United Nations Framework Convention on Climate Change (UNFCCC) in 2012 or the latest report by several non-Annex I countries (year in brackets).