The Effects of Fossil Fuel Consumption-Related CO₂ on Health Outcomes in South Africa

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors.

This work is relevant and of current importance. Mainly, because it relates the environment, energy and health.

My observations after reading your manuscript:

1 - I suggest checking the results presented in item 7. Discussion of Results, as they are different from those presented in the Abstract.

2 - Line 435 – the Latin expression often used by economists “ceteris paribus” which is everything else remains constant. However, it would be better if you put it in English, so that your work is understood by everyone, not just economists.

3 - Lines 23, 24, 25,524, 525, 526, 527, 544, 550, 551, 555, 556, 624, 631, 638, 642, 643, 648 – correct Co2 to CO₂.

Kind regards.

Author Response

Nos	Comments	Corrections	Pages
	Reviewer 1
1	I suggest checking the results presented in item 7. Discussion of Results, as they are different from those presented in the Abstract.	This correction has been made	Page 1
2	435 – the Latin expression often used by economists “ceteris paribus” which is everything else remains constant. However, it would be better if you put it in English, so that your work is understood by everyone, not just economists.	All cases of such occurrence in the manuscript have been corrected	Pages 12, 13, 14 etc
3	Lines 23, 24, 25,524, 525, 526, 527, 544, 550, 551, 555, 556, 624, 631, 638, 642, 643, 648 – correct Co2 to CO2.	124 changes made. Thanks	All appearances of co2 have been corrected to CO2       across pages

 

Reviewer 2 Report

Comments and Suggestions for Authors

This paper establishes both linear and nonlinear ARDL models to explore the relationship between fossil fuel consumption, CO2 emissions, and health outcomes, and it deepens the analysis by using Toda-Yamamoto causality tests. With improvements in clarity of results and stronger connections with policy and theory, this work can provide valuable insights for policymakers and researchers. However, there are still some deficiencies in the paper that need to be addressed:

1. Inconsistencies in Results: The paper reports that CO2 levels have both positive and negative impacts on under-five mortality rates at different times. These results are somewhat contradictory.

2. Limited Discussion on Policy Implications: Although the study concludes with policy recommendations, these are not deeply integrated with the empirical findings. Providing more specific, actionable policy suggestions based on the results could strengthen the paper.

Based on the above issues, the following suggestions for improvement are proposed:

1. Clarify Contradictory Findings: Explain and discuss the reasons behind the different impacts of CO2 on health outcomes in different contexts. A deeper analysis could help clarify these dynamics.

2. Expand Policy Discussion: Provide more detailed, targeted policy recommendations that are directly tied to the specific findings of the study. For example, discuss types of health and environmental policies that could mitigate the observed negative impacts.

Author Response

Nos	Comments	Corrections	Pages
	2nd Reviewer
4	1. Inconsistencies in Results: The paper reports that CO2 levels have both positive and negative impacts on under-five mortality rates at different times. These results are somewhat contradictory.	Sir, The sentence has been restructured. Non linear ARDL result were reported under four different scenarios for the short run result and four different scenarios for the long run result. A careful cross examination were made in response to your comments Sir. I submit that we are in order	Page 19
5	2. Limited Discussion on Policy Implications: Although the study concludes with policy recommendations, these are not deeply integrated with the empirical findings. Providing more specific, actionable policy suggestions based on the results could strengthen the paper.	Policy discussion providing more specific actionable policy based on the result has been included	Pages 19 & 20
6	Based on the above issues, the following suggestions for improvement are proposed: 1. Clarify Contradictory Findings: Explain and discuss the reasons behind the different impacts of CO2 on health outcomes in different contexts. A deeper analysis could help clarify these dynamics.	We have tried to be more detailed in our analysis and to distinctively clarify four different scenarios under which certain results appeared contradicting	Pages 18-20
7	2. Expand Policy Discussion: Provide more detailed, targeted policy recommendations that are directly tied to the specific findings of the study. For example, discuss types of health and environmental policies that could mitigate the observed negative impacts.	We have expanded on health and environmental policies	Pages 20 and 21

 

Reviewer 3 Report

Comments and Suggestions for Authors

Overall, the paper is well written and the English is easy to follow. There are a few stand out issues indicated below.

 

Obvious typos:

 

 decreasing levels of Co2 and FEC in the long run, a 1% increase in Co2 would increase under-five                                                                                                                                 25

watch for typos/inconsistencies, chemically accurate form of the compound needs to be presented (capitalize O).

 

During periods of                                                                                                                24

decreasing levels of Co2 and FEC in the long run, a 1% increase in Co2 would increase under-five            

FEC not designated. Make sure acronyms are explained in the abstract.                                             25

 

the under-five mortality rate per 1000 per-                                                                     581

sons per year in South Africa by 0.418% in the short run, ceteris paribus. This implies that                                                                                                                                       582

 What? How do you know that the infant’s underdeveloped organs are responsible for this?  It could be due to other environmental factors…and the use of obscure latin phrases does not add to clarity here.

 

Generally, the abstract needs to be cleared up and clarified.  As you present findings you do not help clarify that for the casual reader.  One could easily see lines 17-27 as contradictory without a little explanation, for example, without an epidemiological background mortality rate/1000 and mortality rate do not mean much. Also be clear to the casual reader that fossil fuel consumption and CO₂ emissions are not necessarily one and the same.

The literature review was robust and well discussed.

I am wondering if the great deal of detail in regard to statistical methods is beneficial or useful for the average reader?  In a statistical journal I can see it.  The Linear and nonlinear Autoregressive Distributed Lag (ARDL) Bounds, and the Toda-Yamamoto causality test can be used to study the relationship between mortality and climate change. So this is acceptable.

 

However, I wonder about power of the study to detect this 4-6% change?  Was a power calculation done? Assuming the 4-6% and a desirable 0.80 power along with a 0.05 desired significance, and let’s assume a SD of 1? (I believe IM was around 15?)  that would require 4,900 data points.  How many cases of MTR and/or MTR 2 total? This should be discussed as a weakness in the analysis.  The appendices indicate the infant mortality numbers used were only 37 cases..is this correct?!  That needs to be discussed, the term “infant mortality” is used 50 times in the paper but this is not discussed?

There are a great many abbreviations with the tables.  I am wondering if there is a better way to connect abbreviation with content?  Can you use legends with the tables?

I also believe that this paper is going to be difficult for the average environmental scientist, environmental public health professional to benefit from due to the extensive and in-depth statistical focus and little explanation of epidemiological terminology.  Is it possible that two papers could be developed from this work?  A statistical paper and one that is shorter, with less depth in the statistical analysis, more summary about the usefulness and meaning of individual statistical tests and a focus on the meaning for morbidity in this area such as years of life lost and economic impact of same?  Thinking about this from the perspective of the purpose of this journal.

I am not sure measuring CO₂ emissions and Fossil Fuel use measures the variables that need to be measured to really get at how climate impact might impact infant mortality. For example, increase in income from economic productivity needs to be viewed by income level.  And, climate change impacts need to be viewed from the perspective of the actual health threat, for example, infectious disease rates, dangerous weather incidents, food security, water quality and availability.  This is a purely ecological, correlational analysis without a through discussion of the weaknesses of such studies.

Author Response

Nos	Comments	Corrections	Pages
	Third Reviewer
8	decreasing levels of Co2 and FEC in the long run, a 1% increase in Co2 would increase under-five . watch for typos/inconsistencies, chemically accurate form of the compound needs to be presented (capitalize O).	We have corrected all cases of such occurrence	About 124 cases were corrected across all pages
9	During periods of decreasing levels of Co2 and FEC in the long run, a 1% increase in Co2 would increase under-five FEC not designated. Make sure acronyms are explained in the abstract.	We have complied to this instruction in the abstract	Page 1
10	The under-five mortality rate per 1000 per-    sons per year in South Africa by 0.418% in the short run, ceteris paribus. This implies that              What? How do you know that the infant’s underdeveloped organs are responsible for this?  It could be due to other environmental factors…and the use of obscure latin phrases does not add to clarity here.	We have replaced all such Latin words. We have also edited the phrase as underdevelopment of organ is beyond the scope of economics to determine
11	Generally, the abstract needs to be cleared up and clarified.  As you present findings you do not help clarify that for the casual reader.  One could easily see lines 17-27 as contradictory without a little explanation, for example, without an epidemiological background mortality rate/1000 and mortality rate do not mean much. Also be clear to the casual reader that fossil fuel consumption and CO2 emissions are not necessarily one and the same.	We have clarified by defining such terms separately	Page 3
12	I am wondering if the great deal of detail in regard to statistical methods is beneficial or useful for the average reader?  In a statistical journal I can see it.  The Linear and nonlinear Autoregressive Distributed Lag (ARDL) Bounds, and the Toda-Yamamoto causality test can be used to study the relationship between mortality and climate change. So this is acceptable.	Thank you Sir, for the complement
	However, I wonder about power of the study to detect this 4-6% change?  Was a power calculation done? Assuming the 4-6% and a desirable 0.80 power along with a 0.05 desired significance, and let’s assume a SD of 1? (I believe IM was around 15?)  that would require 4,900 data points.  How many cases of MTR and/or MTR 2 total? This should be discussed as a weakness in the analysis.  The appendices indicate the infant mortality numbers used were only 37 cases.is this correct?!  That needs to be discussed, the term “infant mortality” is used 50 times in the paper but this is not discussed?	Logged variables are measured in percentages and non-logged variables are measured in units. Degree of freedom confirmed the appropriate data points needed
13	There are a great many abbreviations with the tables.  I am wondering if there is a better way to connect abbreviation with content?  Can you use legends with the tables?	Legends have been provided as notes to the analysis tables	Pages 10 25
14	I also believe that this paper is going to be difficult for the average environmental scientist, environmental public health professional to benefit from due to the extensive and in-depth statistical focus and little explanation of epidemiological terminology.  Is it possible that two papers could be developed from this work?  A statistical paper and one that is shorter, with less depth in the statistical analysis, more summary about the usefulness and meaning of individual statistical tests and a focus on the meaning for morbidity in this area such as years of life lost and economic impact of same?  Thinking about this from the perspective of the purpose of this journal.	Yes, thanks Sir for the observation. I and my Postdoctoral host will put heads together to produce the second paper on the concepts.
15	I am not sure measuring CO2 emissions and Fossil Fuel use measures the variables that need to be measured to really get at how climate impact might impact infant mortality. For example, increase in income from economic productivity needs to be viewed by income level.  And, climate change impacts need to be viewed from the perspective of the actual health threat, for example, infectious disease rates, dangerous weather incidents, food security, water quality and availability.  This is a purely ecological, correlational analysis without a through discussion of the weaknesses of such studies.	These are limitations under missing variables bias. This will be considered in the subsequent paper.

 

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

It is clear you conscientiously addressed the editorial comments and improved the clarity of this paper in regard to introduction, results (especially tables/abbreviations) and in regard to discussion of and importance of findings.  Please edit the new content very carefully as there are improvements needed in the English writing. Ex: 727...Oxone..I assume you mean ozone and it does not need to be capitalized.  Thank-you for your efforts to improve this work and communicate about an important issue of immediacy to South Africa and the world.

Comments on the Quality of English Language

This is well written overall but needs a second detailed edit.

Author Response

Second Round reviewer’s comment	Corrections Made	Page
Please edit the new content very carefully as there are improvements needed in the English writing. Ex: 727...Oxone..I assume you mean ozone and it does not need to be capitalized.  Thank-you for your efforts to improve this work and communicate about an important issue of immediacy to South Africa and the world.	Thank you Sir. Oxone has been changed to ozone. Further, independent editing has been carried out to help  improve the quality of the manuscript	Page 20