General comments:

This paper presents a European inventory of CH4 and N2O fluxes, which is an update from a recently-published inventory by the same lead author (released in 2021).  The paper thoroughly documents reported emissions, as well as emissions inferred from top-down inversions.  I think the authors could have done a stronger job explaining the differences between this current manuscript and the data synthesis they published just last year in 2021.  This justification was distributed throughout the text, but I think the paper would really benefit from the authors laying out a strong case in the introduction for why this 2022 manuscript is necessary over the 2021 paper.  This being said, I do agree that updating datasets often is valuable for the community, whether or not this includes a thorough re-analysis of trends.  Given the importance of CH4 and N2O to climate change, the keeping emissions inventories current is clearly valuable.

 Specific comments:

Line 216: Please define LULUCF

Table 1 – since this table is meant to highlight data sources, please include references to the data sources.  I also suggest reformatting the table structure.  You could have 3 columns (Emissions sector, data source, data source reference), and then vertically stack the sections for the Anthropogenic BU, Natural BU, and TD

Line 298 – Here you say “to a small extent” is this extend calculation in national inventories?  If so, I suggest including the value here instead of a vague description.  If this contribution isn’t calculated and you are assuming it’s relevance,  can you provide a reference that eutrophication only contributes a small amount to total inland water CH4 emissions?  If not, please rephrase this sentence.

Line 328 – When you say “While many different inversions have been used…” do you mean “While many different inversions exist…”

Line 372 – 373 – It is not clear why you highlight that the first GST will include 2021, given that the GST will be in 2023.  Do you mean that the first GST will include data up until 2021?  If so, why don’t your 5-year means align with a 2017 – 2021 window?

Line 383 – What contributes to the decrease in methane emissions?  It would be helpful to comment at least briefly on what is driving the trend, or point the reader to where in the text you discuss this.

This manuscript is an update on the previous one (Petrescu et al., 2021), which synthesized and compared the estimates of CH4 and N2O emissions over Europe from NGHGI, and BU and TD approaches. The current manuscript follows the nice structure established in the previous version, while with improvements in uncertainty estimation and spatial patterns for posterior CH4 and N2O fluxes from inversions. The manuscript is well written with highlights on the improvements and changes compared to the previous version. A few comments and remarks as follows:

• As the results are mainly for 1990-2019 with few data in 2020, the title should not include 2020.
• The resolution of the figures are low at least in the current pdf version.
• Figure 2 and Figure 10: The bars between 2011-2015 and 2015-2019 are difficult to tell. In particular the yellow uncertainty range are almost invisible. It could be better to use two bars instead one bar for each estimates, which will give clearer information on both mean and uncertainty.
• Figure The colors for inland waters, peatlands and mineral soils, geological emissions and biomass burning are difficult to tell.
• Figure 4 and 13: It is a little surprising that top-down estimates varied a lot between Petrescu et al., 2021a and current study. It would be necessary to explain such differences (model improvements, site observation availability, satellite data availability etc.).
• L586: The differences in the trends could benefit a bit more explanation or discussion.
• L608-612: For such interesting findings, it is necessary to explain it more clearly. The current speculation is not easy to understand.
• L652: “Further” rather than “father”.