5-E Levers: A New Conceptual Model for Achieving Carbon Neutrality in Cities

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Author

The topic and proposed concept of 5-E is very interesting. The topic is current and worth undertaking systematic research on the issue of climate warming. In the introduction, the author outlined the topic well. However, the article contains significant gaps that need to be supplemented and corrected:

1. no keywords

2. lack of final conclusions and recommendations that should appear in this type of article

3. the author did not specify the limitations of his research or outline the direction of further research

4. the author must specify precisely what his contribution is to the development of science and what its impact may be on practice

5. Case study poorly described. should be expanded based on some statistical data

6. it is worth taking into account modern technologies in intelligent buildings in the discussion, which also affects energy efficiency

(cf.  https://doi.org/10.3390/en16134946

7. it is worth paying attention to the greenest means of transport, which are trains, in the context of energy efficiency - https://doi.org/10.3390/en14216875

The article still requires a lot of work, but it is worth the effort due to the importance of the topic

Good luck

Reviewer

Author Response

Reviewer 1

Dear Author

The topic and proposed concept of 5-E is very interesting. The topic is current and worth undertaking systematic research on the issue of climate warming. In the introduction, the author outlined the topic well. However, the article contains significant gaps that need to be supplemented and corrected:

Thank you very much for your revision, your comments and your suggestions. I have written my answers after your points, in blue.

1. no keywords

Keywords have been added

2. lack of final conclusions and recommendations that should appear in this type of article

Final remarks and conclusions have been added in the manuscript.

3. the author did not specify the limitations of his research or outline the direction of further research

The referee is right. Further research and some limitations of the model have been added in the manuscript.

4. the author must specify precisely what his contribution is to the development of science and what its impact may be on practice

My contribution has been to create a conceptual model for ecological transition that allows walking towards climate neutrality in cities, based on isolated and non-interconnected levers. For each lever, research has been done in the scientific literature to demonstrate the effects on carbon reduction, either directly or indirectly. The integration of the isolated levers in a model of 5 levers (the 5E levers) makes it possible to have a strategic vision of the city in which to better define the decarbonization and naturalization projects that a city plans, to better define the projects so that they are integrated into the maximum number of levers.

A paragraph has been added to the manuscript explaining this.

5. Case study poorly described. should be expanded based on some statistical data

The referee is right again. The practical case that is presented in the manuscript has been adopted by the city council by mid 2023. Currently, the 5E levers method has been accepted as the city's strategy to achieve carbon neutrality by 2030, it has defined its current and future projects in this lever structure, but there are no numerical results yet. I have added an explanation explaining better this issue.

I would like to comment that I had the doubt whether to include or not this case study, precisely because right now is just adopting the model, but there is not objective data to analyze.

6. it is worth taking into account modern technologies in intelligent buildings in the discussion, which also affects energy efficiency

(cf.  https://doi.org/10.3390/en16134946

Thank you for this reference. I have added in the Efficiency lever.

 

7. it is worth paying attention to the greenest means of transport, which are trains, in the context of energy efficiency - https://doi.org/10.3390/en14216875

This is a very interesting reference. I have added in the efficiency level, Thank you.

The article still requires a lot of work, but it is worth the effort due to the importance of the topic

Good luck

Thank you.

Reviewer 2 Report

Comments and Suggestions for Authors

The topic of the manuscript “The levers 5-E for urban carbon neutrality” is relevant. However, the aims, scope and type of the manuscript are unclear. It does not indicate if it is a research or review paper, what are the key words, and its scope and aims are unclear.

The scientific contribution and novelty of the manuscript are unclear. The document appears to be a policy report more than a research or review paper. It’s completely focused on one city, appearing to be a policy report for that particular location. For these reasons I believe the manuscript needs to be completely restructured and rewritten to significantly improve on the delivery of the discussed topic.

Some specific comments are as follows.

The novelty and scientific contribution of the manuscript are unclear. It looks more like promotional material for a proposed framework, which development and application are unclear. The literature review for the proposed framework is very superficial and does not contain elements indicating that the chosen levers are the most relevant to achieve the proposed goal. The literature review needs to be significantly improved to justify the use of the proposed levers, its impact on other geographical location and its impact of the proposed goal or achieving carbon neutrality.

The content included in material and methods are a superficial description of policy decisions but does not provide objective parameters or elements for the selection of the proposed levers. This section needs to be significantly improved indicating objective justification for the application of the levers, its measure and control indicators as well as previous application of these parameters.

I was unable to find results in the results section. It looks more like a continuation of the proposed policy for the city indicated in the manuscript. It is unclear how Figure 1 contribute to the results of the study. There is a lack of objective results in this section

The discussion section lacks narrative and focus. It appears to be more a justification of the levers used in the Framework. However, this justification is very superficial, without providing objective reasons for the selection of the parameters and its impact on achieving the proposed goal.

There are several complete paragraphs in italic that don’t have any citation. I am unsure if this was written for this manuscript or if it is a reference, because it has a different tone, appearing to be more policy focused and formal. These paragraphs appear to be disconnected from the narrative of the manuscript. It is very important to carefully cite in the manuscript and when using textual citation enclosed it in quotation marks

The use of internet links in parenthesis in the text is not adequate. This needs to be framed in the citation (reference) format. This reinforces the appearance of the manuscript more as a policy report that a research or review paper.

Comments on the Quality of English Language

English very difficult to understand and narrative need significant improvement. 

Author Response

Reviewer 2

The topic of the manuscript “The levers 5-E for urban carbon neutrality” is relevant. However, the aims, scope and type of the manuscript are unclear. It does not indicate if it is a research or review paper, what are the key words, and its scope and aims are unclear.

Thank you very much for your revision, your comments and your suggestions. I have written my answers after your points, in blue. The keywords have been added. The scope and aim of the manuscript have been improved at the beginning and along of the manuscript.

The scientific contribution and novelty of the manuscript are unclear.

The novelty of the article is the construction of a conceptual model for the ecological transition that leads to climate neutrality in cities, based on the integration and interaction of isolated levers. This integration of the levers under the designation of 5E levers allows for a broader view and a framework in which to place the projects that a city has developed to reduce emissions and increase carbon capture. For each of the levers, the reason why it is essential to consider the lever in question is argued through the scientific literature. In the urban area, a model like this does not exist. Yes, there are efficiency targets, renewable energy generation, etc... but not an interconnected vision of levers to define specific projects, which can satisfy several levers at the same time. The novelty and objectives of the manuscript have been better described.

The document appears to be a policy report more than a research or review paper. It’s completely focused on one city, appearing to be a policy report for that particular location. For these reasons I believe the manuscript needs to be completely restructured and rewritten to significantly improve on the delivery of the discussed topic.

The manuscript does not have this intention that the reviewer comments on, far from it. The manuscript focuses on describing and scientifically justifying the importance of each of the levers for the decarbonization of a city, the importance of not working with isolated levers but integrated as the manuscript proposes. From a scientific point of view, the knowledge of the problem of climate change, its impacts, and the prescription are very clear: Above all, reduce emissions, directly or indirectly, and the capture of carbon from the atmosphere. Based on this scientific knowledge and the proposal of the 5E levers, it is effectively proposed to those who correspond, to the politicians who make decisions that consider this proposal of the strategic framework of the 5E levers, for the scientific evidence that exists and that the manuscript collects. I do not consider this to be a political manifesto.

In relation to the example city, it is the first city to integrate this model as a method to structure its decarbonisation projects and walk towards carbon neutrality in 2030. After the advice and proposal that has been made to the political and managerial team of this town hall, have positively valued developing it. In the manuscript, it has been decided to incorporate this example case to show a city that works in this line, but with no desire for it to be a political manifesto. If the reviewer thinks well, this example case can be deleted and not included. Just commenting, however, that this city managed to get the European Commission to award it the European Green Leaf 2025 city stamp last October, among other reasons for the effort and involvement in trying to decarbonize by 2030, with a commitment defined (they showed the 5E levers methodology described in this manuscript). I have removed any affiliation related to the city, to keep clear that is a scientific manuscript, not any political think.

Some specific comments are as follows.

The novelty and scientific contribution of the manuscript are unclear.

In line with the previous comment, these aspects have been modified and clarified in the manuscript.

It looks more like promotional material for a proposed framework, which development and application are unclear. The literature review for the proposed framework is very superficial and does not contain elements indicating that the chosen levers are the most relevant to achieve the proposed goal. The literature review needs to be significantly improved to justify the use of the proposed levers, its impact on other geographical location and its impact of the proposed goal or achieving carbon neutrality.

The article contains more than 60 citations. It is true that there could be many more, because the scientific knowledge of the impact of projects and actions related to the generation of renewable energy, efficiency, end-of-use electrification, the circular economy, of carbon capture on the environment and sustainability is enormous. The article refers to a sample of this scientific knowledge, but it would be impossible to cover it all. I would kindly ask the reviewer for those key references that are not included and that, according to his judgment, are essential to be included. I would be very grateful. The links in the text have been removed, and many of them moved to a reference.

In relation to the comment that these are not the relevant levers, an effort has been made not to put too many levers, nor too few. The author considers, based on the impact on emissions, that 5 is an appropriate number, and that it integrates in a practical and useful way the key levers for the decarbonisation of a city.

The content included in material and methods are a superficial description of policy decisions but does not provide objective parameters or elements for the selection of the proposed levers. This section needs to be significantly improved indicating objective justification for the application of the levers, its measure and control indicators as well as previous application of these parameters.

The proposed levers are based on the idea of a double action for carbon neutrality: the reduction of emissions to the maximum, and the capture of carbon to the maximum. With this premise, the 5 levers are considered, directly or indirectly related to these two actions. Some of these levers are already included in actions of the European Green Deal, such as electrification, or the SDG, such as clean energy. Each of the levers is justified in the manuscript with research in the scientific literature, arguing why it is important to consider them as a key piece in the conceptual model of the 5Es.

An explanation has been introduced along the lines of what the reviewer suggests, which I appreciate and thanks.

I was unable to find results in the results section. It looks more like a continuation of the proposed policy for the city indicated in the manuscript. It is unclear how Figure 1 contribute to the results of the study. There is a lack of objective results in this section.

The result of this manuscript is the conceptual model that has been proposed as a roadmap for achieving climate neutrality. I agree with the reviewer that there is no numerical data, because this model has only just begun to be applied and deployed in the city discussed in the manuscript, and hopefully it will be adopted by many other cities. It is not intended to be the purpose of this article to show data on the evolution of emissions and carbon capture in each of the levers, because I do not have them. The aim is to present a conceptual model based on interconnected levers, and which has been scientifically proven to reduce emissions when applied. Figure 1 is conceptual, as are Maria Mazzucato's figures when she describes the European missions project, or many other figures that are a conceptual exercise that helps to visualize the interrelationship between different fields of knowledge, in this case, lever actions where to include city projects to achieve carbon neutrality.

I thank the reviewer for his comment. I have added some explanations along the manuscript, and final section of conclusions and final remarks explaining that.

The discussion section lacks narrative and focus. It appears to be more a justification of the levers used in the Framework. However, this justification is very superficial, without providing objective reasons for the selection of the parameters and its impact on achieving the proposed goal.

A review of the discussion in the manuscript has been made, strengthening the narrative and scientific references that objectify the rationale of the 5E conceptual model, based on the scientific knowledge about the topic of the levers. Thanks again to the reviewer for this comment and suggestion.

There are several complete paragraphs in italic that don’t have any citation. I am unsure if this was written for this manuscript or if it is a reference, because it has a different tone, appearing to be more policy focused and formal. These paragraphs appear to be disconnected from the narrative of the manuscript. It is very important to carefully cite in the manuscript and when using textual citation enclosed it in quotation marks.

This aspect has been reviewed and corrected.

The use of internet links in parenthesis in the text is not adequate. This needs to be framed in the citation (reference) format. This reinforces the appearance of the manuscript more as a policy report that a research or review paper.

The reviewer is right. There are too many links in the text. All but one are associated with technical documents of the IPCC, the European Commission. They have been re-referenced to the associated technical reports.

 

Reviewer 3 Report

Comments and Suggestions for Authors

Please see the attached file.

Comments for author File: Comments.pdf

Author Response

Reviewer 3

The author proposed a framework to include and organize urban projects to achieve carbon neutrality based on five interconnected important levers, including energy efficiency, production and consumption of renewable energy, end-of-consumption electrification, circular economy, and encapsulation of CO2.

The work is interesting. However, it lacks supporting results. I suggest the

author to revise the paper considering the following comments:

Providing updated data on the present status of carbon neutrality is recommended.

Many thanks to the reviewer for his/her work and suggestions; they are interesting and very timely. The main objective of the manuscript is to built a conceptual model useful for the carbon neutral in urban areas, defining a framework in which to fit the projects that a city has to achieve this goal, based on the 5 levers that are described and justified based on the scientific knowledge (Data related to the reduction of emissions and CO2 capture related to the levers are in the references). The conceptual model has been started to be applied (at least in the city that appears in the article, hope many other adopt this model in the future), there is currently no data to evaluate the model's support for decarbonization and achievement of neutrality. The current state of carbon neutrality is very variable, depending on each city or municipality. In the case of the city presented as an example of a municipality that has adopted this framework of the 5E levers, there are data: emissions are around 200,000 tonnes, and capture around 40 tons Mobility has a contribution to emissions of 58%, the domestic sphere 20%. But these data are very variable; they change from one city to another.

Figures 1 and 2 show the conceptual schemes of the 5-E levers and what the efficiency lever means, respectively. Results in the form of figures and tables are recommended.

Data and their associated description must support the key findings of the paper.

I totally agree with the reviewer on this comment. But in this case, there is no data to be able to do this analysis. It is an interesting aspect to monitor the reduction of emissions associated with each of the levers after a city applies and develops the 5E model. Several comments about this issue have been added in the manuscript.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Author

Thank you for correcting the article. In my opinion it's good now. I look forward to your further exploration of the implementation of the 5-E model in the future. It's very interesting.

Kind regards

Reviewer

Author Response

Dear Reviewer 1,

 

Thank you very much for your revision. I will continuous working for the dissemination and implementation of these 5E levers.

 

Reviewer 2 Report

Comments and Suggestions for Authors

Some of the review comments were considered in this revised version of the manuscript. However, there are several comments that need to be addressed.

I believe the manuscript is a review paper but it is not indicated the document. The type of manuscript (review or research) should be indicated in the manuscript.

The literature review needs to be significantly improved to justify the use of the proposed levers, its impact on other geographical location and its impact of the proposed goal or achieving carbon neutrality.

Reinforcing the description of the objective parameters or elements for the selection of the proposed levers. This section needs to be significantly improved indicating objective justification for the application of the levers, its measure and control indicators as well as previous application of these parameters.

The discussion section needs to significantly improve on the justification of the levers used in the Framework.  It needs to provide objective reasons for the selection of the parameters and its impact on achieving the proposed goal. 

Section 4.4 has this title “4.4 Ensgering CO2”. In Figure 1 it indicates Ensuaring (CO2). It is important to clarify what is the correct concept. It appears to be ensuring.

The English grammar, construction and narrative needs to be carefully reviewed. It needs significant improvement.

Comments on the Quality of English Language

The English grammar, construction and narrative needs to be carefully reviewed. It needs significant improvement.

 

Author Response

Dear Reviewer 2,

 

Thank you for your comments and suggestions. Bellow my answers, in blue.

Some of the review comments were considered in this revised version of the manuscript. However, there are several comments that need to be addressed.

Thank you very much for your time and effort in reviewing this manuscript. I appreciate so much.

I believe the manuscript is a review paper but it is not indicated the document. The type of manuscript (review or research) should be indicated in the manuscript.

The type of manuscript has been indicated.

The literature review needs to be significantly improved to justify the use of the proposed levers, its impact on other geographical location and its impact of the proposed goal or achieving carbon neutrality.

I kindly believe that the references included to justify the 5 levers that constitute the conceptual model of the 5E levers, are sufficient and appropriate, due to the type of journal in which they are have been published, and because cover the main idea of each of the levers. I agree with the reviewer that there could be much more references, and surely better in some cases. However, the goal of this manuscript is not to do a scientific review of the topics related to each lever; the goal is to propose a new conceptual model that is could be useful and practical for cities to achieve the carbon neutrality. I would be grateful to the reviewer that if there is any essential, or fundamental reference that has been omitted, communicate me to incorporated in the manuscript, reinforcing the reason for choosing the related lever.

Reinforcing the description of the objective parameters or elements for the selection of the proposed levers. This section needs to be significantly improved indicating objective justification for the application of the levers, its measure and control indicators as well as previous application of these parameters.

In the section “final remarks and conclusions”, the following explanation can be found: “Scientific knowledge, of which a small sample is collected in the bibliography, justifies the choice of each of the five levers of the proposed model. This scientific knowledge has demonstrated and defined what actions would be necessary to reduce CO2 emissions, but not in an integrated way but separately. The conceptual model proposed here will facilitate and improve the definition of projects that are part of one or more of the levers, with an integrated view.

The justification for choosing these levers is based on the references along the manuscript. In order to reinforce the selection of these levers the explanation has been enlarged, adding some new references that account that the buildings and transportations have the major contribution to the emissions, and to solve them, efficiency and clean energy is needed.

Concerning the measurement and the indicators for controlling the evolution of the decarbonisation by using the 5E levers, the referee is right; there is not any proposal. However, the same indicators that cities are using for the measurements of the CO2 emissions (sensoring, consumption, etc…) should be used here. If the model “level 5E” is applied in cities, change in the trend of these parameters and indicators will be expected. An explanation have been added in the manuscript.

The discussion section needs to significantly improve on the justification of the levers used in the Framework.  It needs to provide objective reasons for the selection of the parameters and its impact on achieving the proposed goal. 

If I am not wrong, this comment is quite similar than the previous one.

Section 4.4 has this title “4.4 Ensgering CO2”. In Figure 1 it indicates Ensuaring (CO2). It is important to clarify what is the correct concept. It appears to be ensuring.

This mistake has been corrected. The correct term is “Ensnaring”, that means capturing, catching.

The English grammar, construction and narrative needs to be carefully reviewed. It needs significant improvement.

A new native American scientific editor has reviewed the manuscript again. I hope this time English grammar and narrative has been improved definitively.

 

Reviewer 3 Report

Comments and Suggestions for Authors

Your work is good. However, you are strongly encouraged to add supporting results.

Author Response

Dear Reviewer 3,

Thank you very much for your comments and suggestions. This reviewer is right. However, at this stage the results supporting the levers 5E are the scientific literature, that support that by working with these 5E levers connected between them, and as a city framework or strategy, can be useful for the decarbonization and to achieve the carbon neutral challenge as soon as possible. At this stage, I am sorry but I have not data for supporting the model, only the scientific literature.

In order to not confuse the goals of the manuscript, I have changed the title adding conceptual mode, to “5-E Levers: A New Conceptual Model for Achieving Carbon Neutrality in Cities”