In “Ensemble estimates of global wetland methane emissions over 2000-2020,” Zhang and co-authors simulate global methane wetland emissions using 16 process-based wetland models with varying levels of complexity that are participating in the Global Carbon Project. Authors simulate wetland methane emissions for 2000-2020 and simulate the decadal changes in emissions and their large-scale drivers. The modeling ensemble shows an increase in 2010-2020 vs 2000-2010 emissions, and that temperature is the primary driver followed by precipitation and atmospheric CO2 concentration. Authors show that these changes and the drivers are generally support by inversions and observational evidence.

Overall, I think this is a well written study and useful study. In my opinion, it should be accepted after addressing a few comments and questions.

Overall comments

The multiple linear regression lacks detail in how the predictors were selected, so it is unclear how robust those conclusions are. Authors choose global mean temperature, global total precipitation, and mean atmospheric CO2 concentration as the predictors, and then state that modeled eCH4 was “primarily associated” with those variables (line 340), but were those the only variables tested? In that case, did the exercise reveal anything new? Authors say that “other confounding drivers might influence eCH4 as well, such as solar radiation, wind speed, and nitrogen deposition” (line 325), but don’t explore these as predictors. Could authors provide more justification for their choice of the three main predictors? Did authors test model performance after leaving any of these predictors out, or adding any of the additional predictors they mentioned? 

How do the ensemble modeling results for the 2020 surge compare with other studies that used satellite data to interpret the surge? Authors mention Peng et al. 2022. In addition, Feng et al. 2023 (https://doi.org/10.5194/acp-23-4863-2023) and Qu et al 2022 (https://doi.org/10.1088/1748-9326/ac8754) attribute the surge to emissions, largely from wetland and water sources in Africa. A note on how your results agree or not would be useful given the attention in this manuscript and in the literature on the 2020 surge.

Minor comments

Line 52-53: This seems like a strong statement. I think this has been addressed, for example in inversions and in the authors’ previous works, though perhaps not in the way it is addressed here. Consider being more specific.

Line 55-56, “with an average decadal increase…”: this sentence is a little unclear.

Line 97-98: Y Zhang et al. 2021 (https://doi.org/10.5194/acp-21-3643-2021), using GOSAT, is a useful comparison here.

Line 136-137 “different prescribed parameters”: Does this mean that each model has a different set of parameters and inputs, or that a different set of parameter values is given to each model? The current statement is vague. 

Line 144: Authors mention high correlations for the temperate region and high latitudes, but what about the tropics with the most emissions? Ensemble mean agreement with GIEMS2 in that region seems important, but it is not discussed and it is hard to tell the performance of the tropics from Figure S1.

Line 205 and apparent Q10: Could authors comment on the choice ambient vs soil temperature here? Given the hysteresis effect, and evidence that methane emissions follow soil temperature rather than air temperature, soil seems the more logical choice, but I may be misunderstanding.

Line 226, “Suggesting enhanced wetland-CH4 sensitivity under climate change”: To me, authors haven’t demonstrated that the larger IAV in the second decade considered is evidence of larger sensitivity under climate change. The statement may be true, but I don’t think authors have demonstrated it, so I suggest adjusting the statement or providing more evidence.

Figure 2: Could authors add identifying markers for the regions in panels c,d to the maps?

Line 317-318, “with a range of -0.4 and 9.0 Tg…”: Is this the distribution of coefficients among all the wetland models?

Figure 3: It’s unclear what the Gaussian density distribution curves represent, could more description be added to the caption? In panel b, the dashed lines are too faint to distinguish.

Line 411-413, “Furthermore…eCh4”: The meaning of this sentence is unclear.

Lines 418-421: The MLR analysis seems to show a lower relative importance of the CO2 fertilization effect. Could authors reconcile the MLR analysis with the factorial analysis on this point?