I’d like to thank the authors for the attention, time and effort put into answering all my questions and remarks. The manuscript has substantially improved from previous versions and it's clear it has been extensively revised. I still have a couple of comments and suggestions that would improve readability, but nothing major.
Abstract ----------------------------------------------------------------
I think the Abstract would benefit with more detail and the key take-away messages. For instance, it is not clear that, amongst the papers that evaluated fire emissions, most were on a global or continental scale and there were only 2 papers that explicitly analysed fire emissions in the Cerrado. This severe lack of literature on the issue (especially compared to other ecosystems, as the authors reinforce), is one of the key take-aways of the paper in my opinion. Could also mention that most of these studies were conducted by international teams and a considerable number did not include Brazilian authors nor institutions based in the Cerrado biome.
Minor comments:
Line 12: I suggest changing “countries” to “ecosystems”.
Line 12: I think it’s missing a phrase stating what this study is proposing to do (e.g. “Here, we propose to bridge this gap by (…)”), to precede results on the following sentence “Of 77 systematically reviewed papers (…)”.
Line 12: “papers” is duplicated.
Line 12: Is the 54% correct? Lines 290-291 state 46 papers for “fire dynamics” and 12 for “management and policy” (that is, 58 total for both categories). If some of these are double counted, then this number should figure somewhere in the manuscript for clarification.
Line 13: I suggest “While these are key to provide a holistic (…)”.
Line 16: “Methodological techniques” seems redundant (also on the legend of Figure 5). I suggest “Most papers employ different methods (…)”.
Line 18: I suggest rephrasing to “More research is required to understand fire dynamics and emissions in the Cerrado and identify potential mitigation measures (…)”.
Line 19-21: While I agree that land surface models would benefit from including fire management, I’d say it’s more urgent that the scientific community works to properly quantify emission factors for Cerrado’s vegetation types and across fire types (more/less intense fires, EDS/LDS fires, etc).
Introduction ----------------------------------------------------------------
I think the Introduction is quite big and could be slightly summarized and re-organized. I propose to relocate the following paragraphs: paragraphs from lines 55 to 77 could follow the first paragraph (lines 23-30), characterizing the Cerrado biome and fire activity. Then, keep paragraphs from lines 31-54, discussing fire emissions in Cerrado. And finally, paragraphs from lines 78-104.
Minor comments:
Line 24: I suggest “Around 49% of Cerrado (965,783 km2) is covered (…)”.
Line 37: “However” seems misplaced. There is no contradiction.
Line 38: This phrase is confusing as is. I suggest something along the lines of “Thus, understanding the contribution of each of these greenhouse gases, especially CO2, in fire emissions is essential, especially in fire-prone ecosystems such as Cerrado.”.
Line 40: I suggest rephrasing this sentence, deleting “immediate emissions” and “fire participates”. Something along the lines of “Beyond emissions, fire interacts with several components of the carbon cycle, shaping complex interactions and carbon balance over time.”.
Lines 42-44: Needs a reference.
Line 70: Define IPCC.
Line 78: As it’s the first time this term is used in the article, and because it has not been said yet that this is one of the categories identified in the study, it is not clear what “fire dynamic parameters” is. I propose changing to “understanding fire dynamics provides grounding (…)”.
Lines 80-82: Is this not a result?
Line 80: I suggest changing “cycle” to “budget”.
Line 84: GHG is not defined.
Lines 87-88: Reference?
Lines 89-91: I believe this belongs in Discussion.
Line 94: I suggest “what are the parameters used (…)”.
Line 95: You mean “pyrogenic carbon”? If so, this term should be employed earlier in the text.
Line 101: I suggest “describe fire parameters”.
Methods ----------------------------------------------------------------
I think this section presents my only remaining disagreement with the authors: the use of “natural areas”. I disagree with the authors that “A focus on natural areas allows for a clearer evaluation of how fire interacts with ecosystem function, rather than being confounded by human-driven fire use.”, as fires in natural areas of the Cerrado are still, in their vast majority, human-driven (e.g. see Arruda et al. 2024: “Natural vegetation was the most affected, primarily due to human-driven ignition during the dry season”).
Nevertheless, I completely agree with the point the authors make in “Knowledge Gaps in Fire Regimes and Emissions” and add that it should be included in the Discussion. However, I don’t think it justifies the use of “natural areas” in the study.
I don’t think that including anthropogenic burning would change the scope of the article, as the study already considers anthropogenic burning. As mentioned before, ignitions in the Cerrado are overwhelmingly human and, as such, any discussion of fire and fire emissions in the biome will consider anthropogenic-driven fires, unless it specifically evaluates lightning-induced fires or “natural fire regimes”. Additionally, most papers found in the review process include burning in anthropogenic land covers and discuss the human components of fire. As there is no keyword in the review process for this, this is not explicitly accounted for throughout the manuscript. Moreover, there is no other mention of “natural areas” in Results or Discussion (except for the repetition of the research question). As such, I don’t see the need to make this distinction, when this is not reflected in the Methods, Results and Discussion.
Minor comments:
Lines 139-140: I wouldn’t say “there is greater certainty”, it’s the yearly availability of these products that start in 2003.
Lines 192-197: This information should come earlier in the Methods section, maybe after line 142.
Lines 192-197: Please clarify the different between Review and Perspective papers for the reader.
Line 203: I suggest just using “fire dynamics” instead of “fire dynamics parameters”.
Line 203: I think the authors meant “research”.
Results ----------------------------------------------------------------
Minor comments:
Line 229: How was the trend estimated (linear regression, Mann-Kendall, etc)? This information should be added to Methods.
Line 237: There is no contradiction, as Mistry et al. (2019) also extrapolates from a smaller region to a larger.
Figure 4: Please upload with higher resolution.
Line 291: I suggest rephrasing to “(…) policy. It’s worth noting that 24 papers are related to more than one topic.”.
Lines 298-299: This sentence belongs in the Discussion.
Line 301: Please clarify what “modelling” means in this context. Statistical modelling, process-based models?
Line 313-314: I think this sentence belongs in the Discussion and Conclusion.
Line 325: “emissions”
Line 379: Use the acronym previously defined for modified combustion efficiency.
Line 382: Use the acronym previously defined for late dry season fires.
Line 384: The values are so similar it is relevant to show the uncertainty range if there is one.
Lines 385-386: It is said that the values are underestimated, and the following sentence says these are high. Seems contradictory.
Line 389: I suggest “(…) estimating emissions (…)”.
Line 428: This seems to entail that the previous studies did not use FRP as a measure of fire intensity, which is not the case.
Lines 433-435: If FRE is not used in any study I don’t see why its definition is needed here.
Lines 448-452: I think this belongs to the Discussion.
Figure 6: I now agree with the authors that the figure is essential to report findings. However, I still have reservations about the arrows, namely those going to Burned Area and Combustion completeness and then Fire emissions. You found in the literature that there are other parameters (e.g. FRP; emission factors) used to estimate Fire emissions. Why are they not considered here?
Legend of Figure 6: I don’t think it’s “fire spreads from forests to grasslands” but rather “fire spread increases from forests to grasslands”.
Line 498: Is the 43% correct? Isn’t it 43 papers out of 77?
Line 520: Acronym already defined previously.
Lines 526-530: Seems Discussion to me.
Table 2: I think it would be interesting a discussion on the similarity/disparity of the values found in the literature, and how they compare to broader estimates (from savannas in South America, for example).
Table 2: Please clarify that Gomes et al. (2020a) does not estimate emissions.
Line 579: Please remove “and even in the units”. Gomes et al. (2020a) does not estimate emissions but rather the amount of carbon released in combustion, which is a parameter that can and will be used to estimate emissions.
Lines 579-584 and 592-594: Seems Discussion to me.
Line 602: Define IFM.
Line 619: “small-scale”
Line 620: This section of the sentence is confusing: “fire regime characteristics of fire management activities”. Maybe “(…) studies that estimate activities associated with fire management activities, such as prescribed burning (…)”.
Lines 627-629: The results of Santos et al. (2021) are valid for which region? Better to mention.
Lines 630-636: Please highlight that this is a result. That is, that this is what the papers cited discuss and inform.
Discussion ----------------------------------------------------------------
Lines 640-642: The authors mention a “broad and holistic understanding of the role of these emissions in the carbon budget on regional, national and global scales” however, up to this section of the manuscript, there has been no such discussion. As per my comment for Table 2, I suggest writing a paragraph on this.
Line 658: I wouldn’t say 31% of papers is “most”.
Lines 673-674: Slightly misleading sentence. Two papers were identified that estimate emissions in Cerrado. Even if only one goes back to 1985.
Line 693: First time that pyrogenic carbon is mentioned in the text. If the authors want to use this term, I suggest using it earlier in the manuscript.
Line 714: Use the acronym previously defined.
Line 724: I would also add to the discussing the findings of Andela et al. (2017; A human-driven decline in global burned area), where they found that a recent decrease in savanna fires worldwide is driven by human occupation.
Table 3: Shouldn’t FRP be added to the column on the left?
Conclusion ----------------------------------------------------------------
I would suggest reinforcing the take-away messages in the Conclusion as well (similarly to the Abstract). |
General comments
The main goal of this manuscript is to perform a systematic and comprehensive literature review on fire emissions in the Brazilian Cerrado, and put these emissions into perspective of the global carbon budget. Given that Brazil is the largest contributor to land use (LU) emissions, the role of fire in LU emissions, and Cerrado as the largest contributor to Brazil's annual burned area, this assessment is relevant and of interest to the scientific community. To my knowledge, there is no such assessment yet, and this study could potentially contribute significantly to understanding the current state of fire emission estimates in the biome and identify research gaps. Unfortunately, I don't think the authors were successful in doing so. I will detail my main concerns with this manuscript below:
Specific comments
Technical corrections