Modeling and Monitoring CO2 Emissions in G20 Countries: A Comparative Analysis of Multiple Statistical Models
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThere is a typo error in the abstract for CO2. Please check and revise.
The in-text citation format is incorrect. Please check and follow the journal format.
The major objectives of this study are to find a suitable model which best describe the relation of the carbon emission and various factors in the G20 countries, to quantify the impacts of selected factors on carbon emission and finally to investigate the impacts of these factors on carbon emission with time.
Figure 1 shows the geographical location of the G20 countries, which clearly represents the locations with different highlights.
Both MAE and RMSE are parameters that commonly used in MLR and statistical models.
Figure 2 shows the spatio-temporal trends of mean annual CO2 emissions from 1971 to 2021, including a comparison of different subdivided periods. Can the authors explain which model were applied to generate these graphs?
Figure 3 shows Relationship between CO2 and other explanatory variables. This is a scatterplot of x and y variables, but the correlation coefficient (R) or coefficient of determination (R2) were not shown.
Section 3 shows the result section, but the discussion section is clearly missing.
Table 4 shows the Summary of Model Performance Metrics. The model with the best result should be either bold of highlighted for the better visibility for the reader.
The limitation of this study was not discussed in the conclusion section, which need to be revised. Also, the number of references cited seemed to be low for a scientific article. Some experiments are missing and need to be improved.
Comments on the Quality of English LanguageThere are many spelling and grammar errors in the text which needs to be revised.
Author Response
Comments 1: [There is a typo error in the abstract for CO2. Please check and revise.]
Response 1: [Thank you for bringing this issue to our attention. Upon review, we have found that the discrepancy was in the title of the article, rather than the abstract. We appreciate your diligence and have made the necessary corrections.]
Comments 2: [The in-text citation format is incorrect. Please check and follow the journal format.]
Response 2: [Thank you for pointing out this issue. We have revised the citation format according to the journal's guidelines using EndNote software.]
Comments 3: [Figure 1 shows the geographical location of the G20 countries, which clearly represents the locations with different highlights.]
Response 3: [Thank you for suggesting a more appropriate citation for Figure 1. We have now replaced it accordingly.]
Comments 4: [Both MAE and RMSE are parameters that commonly used in MLR and statistical models.]
Response 4: [This has been corrected in the revised manuscript as suggested by the reviewer as below: Both MAE and RMSE are metrics used to evaluate prediction error. RMSE penalizes larger errors more heavily than MAE.]
Comments 5: [Figure 2 shows the spatio-temporal trends of mean annual CO2 emissions from 1971 to 2021, including a comparison of different subdivided periods. Can the authors explain which model were applied to generate these graphs?]
Response 5: [These graphs were created using the symbology tools in ArcGIS Pro software using the available data.]
Comments 6: [Figure 3 shows Relationship between CO2 and other explanatory variables. This is a scatterplot of x and y variables, but the correlation coefficient (R) or coefficient of determination (R2) were not shown.]
Response 6: [We did not apply any models in this step. Instead, we created plots with CO2 emissions on the y-axis and the explanatory factors on the x-axis. This initial step helps us visually assess the relationships between the response variable and the explanatory factors. ]
Comments 7: [Section 3 shows the result section, but the discussion section is clearly missing.]
Response 7: [Thank you for your feedback. We have added a comprehensive discussion section to the manuscript as per your suggestion.]
Comments 8: [Table 4 shows the Summary of Model Performance Metrics. The model with the best result should be either bold of highlighted for the better visibility for the reader.]
Response 8: [The model with the best result has been highlighted in the revised manuscript in the light of reviewer suggestion.]
Comments 9: [The limitation of this study was not discussed in the conclusion section, which need to be revised. Also, the number of references cited seemed to be low for a scientific article. Some experiments are missing and need to be improved.]
Response 9: [Discussion about the limitations is an important aspect of scientific research which can provide an opportunity for other researchers to improve the existing literature.
We have added a comprehensive discussion section in the revised manuscript where we discussed the limitations of this study as well.
New references have been added to the revised manuscript which are mostly related to the potential impacts of CO2 emissions. We hope that the references are enough now.]
Comments 10: [There are many spelling and grammar errors in the text which needs to be revised.]
Response 10 : [Thank you for your feedback. We have thoroughly revised the manuscript to correct the spelling and grammar errors.]
Reviewer 2 Report
Comments and Suggestions for AuthorsIn this article, the authors have successfully used multiple statistical models to model and monitor CO2 emissions in G20 countries. The findings have significant implications for decision-makers in global carbon emissions and monitoring. This article has a clear organization, some revisions are necessary for the publishing of this manuscript.
1. In this article, there are many cases that the numbers in CO2 have no subscript, please check it carefully. For example, this situation occurs in title and references.
2. In the fourth paragraph of the introduction, “we did not find a study which address the above mentioned concerned about the carbon emission of G20 countries” has been mentioned, it is too absolute. Please read more literature and carefully revise it.
3. The second paragraph in the result is too long. Please segment it according to its content and logical relationship.
4. The emission data of CO2 is provided by other institutions and not tested by the author. Therefore, it is not necessary to describe the data in too much language in the conclusion, but rather focus on describing the results obtained through modeling in this article.
5. In the reference, there are many cases that references format is incorrect, please check it carefully. For example, this situation occurs in references 14, and 21.
Author Response
Comments 1: [In this article, there are many cases that the numbers in CO2 have no subscript, please check it carefully. For example, this situation occurs in title and references]
Response 1 : [Thank you for pointing out the issue with the CO2 subscript. We have carefully reviewed and corrected the instances in the title and references as you suggested.]
Comments 2: [In the fourth paragraph of the introduction, “we did not find a study which address the above mentioned concerned about the carbon emission of G20 countries” has been mentioned, it is too absolute. Please read more literature and carefully revise it.]
Response 2 : [We tried our best to read the relevant literature about this issue. As we are comparing various models and then quantifying the impacts of covariates on the CO2 in the G20 countries. We modified our statement in the revised manuscript as
“To the best of our knowledge, we did not notice studies which address all of the above mentioned concerned about carbon emission of G20 countries together”.
This means that studies addressed these issues separately or in combinations but not all together at the same time. Therefore, we made this statement in this study.]
Comments 3: [The second paragraph in the result is too long. Please segment it according to its content and logical relationship.]
Response 3 : [Thanks to the reviewer for highlighting suggestion. We have segmented the second paragraph in the results section according to its content and logical flow, as you suggested.]
Comments 4: [The emission data of CO2 is provided by other institutions and not tested by the author. Therefore, it is not necessary to describe the data in too much language in the conclusion, but rather focus on describing the results obtained through modeling in this article.]
Response 4 : [The text about data description has been reduced in the conclusion section as suggested by the reviewer. In contrast, the text about modelling has been increased in the conclusions section. ]
Comments 5: [In the reference, there are many cases that references format is incorrect, please check it carefully. For example, this situation occurs in references 14, and 21.]
Response 5 : [Thank you to the reviewer for pointing out this issue. We have revised the citation format according to the journal's guidelines using EndNote software.]
Reviewer 3 Report
Comments and Suggestions for AuthorsThe present manuscript provides CO2 emissions per capita have declined in recent times in these developed countries. The highest annual average CO2 emission ranges from 14.33 to 22.16 over the period 1971- 1980, while in the recent period from 2011 to 2021, the highest annual average CO2 emissions class has declined, ffuctuating between 12.63 and 17.95 metric tons per capita. For CO2 modelling and monitoring, PFEM and PMEM outperform the other models. These models consistently performed well as compared to other models such as MLRM, QRM, and PREM using a variety of model selection criteria such as MAE, RMSE, AIC, and BIC. This manuscript can be considered to be accepted by Sustainability after considering the following issues.
1. The spatio-temporal trends of mean annual CO2 emissions from 1971 to 2021, including a comparison of different subdivided periods. Why no recent two years?
2. It has been noted that there is a link between CO2 emissions and explanatory variables such as NREN, GDP, and URB. However, why REN has no substantial effect on CO2 emissions?
3. The objective is to investigate whether the inffuence of the selected factors such as NREN, REN, GDP and URB, on carbon emission has changed over time or not. How is about the condition changing?
Comments on the Quality of English Languageok
Author Response
Comments 1: [The spatio-temporal trends of mean annual CO2 emissions from 1971 to 2021, including a comparison of different subdivided periods. Why no recent two years?]
Response 1: [The data were only available up to 2021, that is why the most recent two years were not included.]
Comments 2: [It has been noted that there is a link between CO2 emissions and explanatory variables such as NREN, GDP, and URB. However, why REN has no substantial effect on CO2 emissions?]
Response 2: [
Thank you for your insightful comment. According to our PFEM and PMEM analyses, the effect of renewable energy (REN) on CO2 emissions was positive during the first period (1971-1995). However, in the recent period (1996-2021), the effect of REN on CO2 emissions has become negative, though it has not yet reached statistical significance. This indicates that over time, the relationship between REN and CO2 emissions has shifted to an inverse relationship. We assume that REN will have a significant impact on CO2 emissions in near future.]
Comments 3: [The objective is to investigate whether the inffuence of the selected factors such as NREN, REN, GDP and URB, on carbon emission has changed over time or not. How is about the condition changing? ]
Response 3: [
This is not the objective of this study but this is an important point. This depends on how much the conditions we would like to change and that will reflect the changes in the relationship. Based on this point one can develop future scenarios about CO2 emission while having conditional information about the covariates, however, this is beyond the objectives of this study. Nevertheless, this is an important and potential topic for future research.]
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe authors clearly did not take into consideration of the previous reviewer's report, which is very disappointing. The concern to include correlation coefficient (R) and coefficient of determination (R2) were ignored. Also, there are many spelling mistakes which should not be present. The limitation of study should be included in the conclusion section, not in the discussion section. Table 1 to 3 should be integrated and be better represented. It is currently not very clear and should be revised.
Author Response
Comments 1: [ The concern to include correlation coefficient (R) and coefficient of determination (R2) were ignored.]
Response 1 : [Thank you for your valuable feedback. In response to your suggestion, we have included the correlation coefficient (R), the coefficient of determination (R²), and the model equation in Figure 3 to provide a clearer representation of the relationship between CO2 and covariates]
Comments 2: [There are many spelling mistakes which should not be present]
Response 2 : [Thank you for your valuable feedback. We have carefully reviewed the manuscript and corrected all spelling mistakes.]
Comments 3: [The limitation of study should be included in the conclusion section, not in the discussion section]
Response 3 : [Thank you for your valuable feedback. We have removed the limitations from the discussion section and included them in the conclusion section as per your suggestion. We appreciate your guidance in improving our manuscript.]
Comments 4: [Table 1 to 3 should be integrated and be better represented. It is currently not very clear and should be revised.]
Response 4 : [Thank you for your insightful feedback. We have carefully reviewed your suggestion regarding Tables 1 to 3. Table 1 presents descriptive statistics, while Tables 2 and 3 provide various model parameters results across different intervals. We believe that separating these tables enhances clarity and allows readers to easily distinguish between the descriptive statistics and the model parameters. ]
Round 3
Reviewer 1 Report
Comments and Suggestions for AuthorsThe authors have revised the paper accordingly to the previous review report and I have no further objection for this paper to be accepted. Please double check the grammar and spelling throughout the text.
Author Response
Comments : [ Please double check the grammar and spelling throughout the text. ]
Response : [ Dear Reviewer, Thank you for your valuable feedback on our article. We have thoroughly reviewed the entire manuscript and corrected all grammar and spelling errors as per your suggestion. We appreciate your attention to detail and hope that the revised version meets your expectations.
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