Integrating Nature-Based Solutions into Circular Economy Practices: A Case Study on Achieving Net-Zero Emissions at the Asian Institute of Technology

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. This paper analyzes a net-zero emission program implemented on the campus of Asian Institute of Technology. As a case study, this paper is in general clearly written and informative.  Some minor points remain to clarify or improve.
2. The university social responsibility (USR), campus sustainability, and environmental education backgrounds and references can be further cited and introduced.
3. This paper actually uses the baseline approach to estimate the carbon emission benefits. The academic papers of the baseline estimation should be further cited and briefly introduced around the current pp. 3-4.
4. For the carbon emission and reduction, in practice there are practical guidelines such as ISO, GRI, etc. On pp. 4-10, there are formulas to compute the baseline line and reduction amounts. It is not clear which international guideline or system this paper is following.  Of course, the authors may have their own model for estimation.  However, in the industry practice an enterprise usually need to clearly indicate the methodology of an international guideline that it is following for the third party verification.
5. Table 4 reports the parameter values. Are these parameters obtained from local Thailand environments or from usual international standards? 
6. Figures 4 to 6 show the carbon reduction benefits and net zero-pathways. Are these results better or worse than a benchmark project in Thailand or another country?
7. Section 4 indicates the policy implications. However, Asian Institute of Technology is an educational institute.  It will be more informative to talk more about the environmental education aspects.
8. If possible, all figures should be made bigger in sizes to make it easier for readers.
9. The current conclusion is very short with only half of a page. Moreover, it mainly reports the numerical results without too many managerial and educational implications.  The conclusion section should be further enriched to be of at least one full page.
10. After revision, this case study can provide an interesting and informative reference for foreign universities to read.

Author Response

Comments and Responses

We sincerely thank the reviewers and the editor for their valuable comments and constructive feedback, which have greatly contributed to improving the quality of our manuscript. We have carefully considered each suggestion and have made the necessary revisions to enhance the clarity, relevance, and impact of our study. We appreciate the time and effort invested in providing such insightful and detailed feedback.

We now address each comment in detail below.

 

Reviewer 1

Comments 1: This paper analyzes a net-zero emission program implemented on the campus of Asian Institute of Technology. As a case study, this paper is in general clearly written and informative.  Some minor points remain to clarify or improve.

Response 1: We thank the reviewer for the positive feedback and for acknowledging the clarity and informative nature of our case study. We appreciate your valuable insights, and we have carefully addressed each of the minor points to improve the manuscript.

Comments 2: The university social responsibility (USR), campus sustainability, and environmental education backgrounds and references can be further cited and introduced.

Response 2: We thank the reviewer for this insightful comment. In response, we have enhanced the Introduction section by discussing the relevance of University Social Responsibility (USR), campus sustainability, and environmental education in the context of net-zero emissions. We highlighted how educational institutions contribute to environmental stewardship and societal change, aligning with AIT's sustainability goals. The additional background on USR, campus sustainability, and environmental education was inserted in the Introduction section, after the paragraph discussing AIT's commitment to net-zero emissions. We also included citations from recent literature (Lozano et al., 2020; Leal Filho et al., 2021; Barth & Rieckmann, 2016) to provide a robust contextual foundation.

Comments 3: This paper actually uses the baseline approach to estimate the carbon emission benefits. The academic papers of the baseline estimation should be further cited and briefly introduced around the current pp. 3-4.

Response 3: Thank you for this valuable suggestion. We agree with the comment and have revised the Materials and Methods section to include a brief introduction to the baseline estimation approach. Specifically, we have explained its relevance in carbon accounting and introduced different types of baselines—retrospective, projected, and stable baselines—used in this study. To strengthen the theoretical foundation, we have also cited relevant academic papers (Brown et al., 2020; IPCC, 2019; Chen et al., 2021). The additional explanation and references were inserted in the Materials and Methods section, specifically in the subsection detailing baseline emission levels at the AIT campus (pages 3-4).

Comments 4: For the carbon emission and reduction, in practice there are practical guidelines such as ISO, GRI, etc. On pp. 4-10, there are formulas to compute the baseline line and reduction amounts. It is not clear which international guideline or system this paper is following.  Of course, the authors may have their own model for estimation.  However, in the industry practice an enterprise usually need to clearly indicate the methodology of an international guideline that it is following for the third party verification.

Response 4: Thank you for this valuable comment. We recognize the importance of aligning carbon emission and reduction calculations with established international guidelines for third-party verification. In this study, we followed the Greenhouse Gas Protocol (GHG Protocol) as the primary framework for carbon accounting and reporting. Specifically, we adhered to the guidelines for Scope 1, Scope 2, and Scope 3 emissions, ensuring consistency and comparability with international standards. Additionally, the emission factors used were sourced from the Thailand Greenhouse Gas Management Organization (TGO), which aligns with the Intergovernmental Panel on Climate Change (IPCC) guidelines, ensuring the credibility and accuracy of the calculations. For baseline emissions and reduction projections, we applied the Autoregressive Integrated Moving Average (ARIMA) method, which is widely recognized for its reliability in time series forecasting. While our study introduces a holistic carbon balance approach that integrates projections, removals, and circular economy principles, we ensured that all calculations are traceable to internationally recognized methodologies. We have now included this clarification in the Materials and Methods section to enhance the transparency and replicability of our approach.

Comments 5: Table 4 reports the parameter values. Are these parameters obtained from local Thailand environments or from usual international standards?

Response 5: We thank the reviewer for the clarification. These parameters are obtained from usual international standards.

Comments 6: Figures 4 to 6 show the carbon reduction benefits and net zero-pathways. Are these results better or worse than a benchmark project in Thailand or another country?

Response 6: Thank you for this valuable comment. We acknowledge the importance of contextualizing our findings through comparative analysis. However, as this study focuses on a small-scale urban institution, it is not feasible to directly compare the net-zero pathways with country-level initiatives, which involve broader economic sectors and larger emissions baselines.

Nonetheless, to provide relevant context, we added a discussion comparing AIT’s net-zero pathway with Thailand's national targets. Our projections indicate that AIT can achieve its net-zero emission target earlier than Thailand as a whole, which aims for carbon neutrality by 2050 and net-zero emissions by 2065. This contrast underscores the potential effectiveness of tailored NbS strategies at the institutional level, highlighting the role of small-scale urban initiatives in contributing to broader national and global sustainability goals.

Comments 7: Section 4 indicates the policy implications. However, Asian Institute of Technology is an educational institute.  It will be more informative to talk more about the environmental education aspects.

Response 7: Thank you for this valuable suggestion. We agree with the comment and have revised the Policy Implication section to include “4.3 Environmental Education Aspect” by discussing implementations of nature-based solutions to achieve net-zero emissions at the AIT campus offer valuable environmental education opportunities. For example, engaging student in climate change action through implement the plan with student participation via tree planting events and use the finding from each NbS strategy for case studies.

Comments 8: If possible, all figures should be made bigger in sizes to make it easier for readers.

Response 8: We thank the reviewer for the comment. However, the current figures are readable, and organization of figures are more appropriate in this current form. Therefore, we haven’t addressed this comment.

Comments 9: The current conclusion is very short with only half of a page. Moreover, it mainly reports the numerical results without too many managerial and educational implications.  The conclusion section should be further enriched to be of at least one full page.

Response 9: Thank you for this valuable suggestion. We agree with the comment and have revised the Conclusion section to 1 full page, with additional many managerial and educational implications and limitations and suggestions for further research.

Comment 10: After revision, this case study can provide an interesting and informative reference for foreign universities to read.

Response 10: We thank the reviewer once again for the positive feedback and for acknowledging the clarity of this paper.

Reviewer 2 Report

Comments and Suggestions for Authors

I am sharing my comments.

Comments for author File: Comments.pdf

Author Response

Comments and Responses

We sincerely thank the reviewers and the editor for their valuable comments and constructive feedback, which have greatly contributed to improving the quality of our manuscript. We have carefully considered each suggestion and have made the necessary revisions to enhance the clarity, relevance, and impact of our study. We appreciate the time and effort invested in providing such insightful and detailed feedback.

We now address each comment in detail below.

Reviewer 2

Integrating Nature-Based Solutions into Circular Economy Practices: A Case Study on Achieving Net-Zero Emissions at the Asian Institute of Technology

Comments 1: The document evaluates the integration of nature-based solutions into circular economy practices to achieve net-zero emissions by 2030. The case study was conducted at the Asian Institute of Technology. They applied the Autoregressive Integrated Moving Average (ARIMA) method for forecasting carbon emissions from 2023 to 2050. Although Nature-Based Solutions is a trending topic and its connection with the circular economy is engaging, the present article still needs improvement before being considered for publication. The following comments might help increase the chance of publication.

Response 1: We thank the reviewer for the positive feedback and for acknowledging the clarity and informative nature of our case study. We appreciate your valuable insights, and we have carefully addressed each of the minor points to improve the manuscript.

Introduction

Comments 2: The objectives of the present study are presented very well. However, the research's contributions and its novelties should also be presented in the same way.

Response 2: We thank the reviewer for this valuable comment. In response, we have expanded the Introduction section to explicitly state the research contributions and novelties of this study. We highlighted contributions and novelties as follows: First, a holistic carbon balance approach by integrating carbon accounting, projections, and removals to provide a comprehensive pathway toward net-zero emissions for small urban institutions, unlike previous research that treats emissions and sequestration separately, this study evaluates both components in a unified framework. Second, a scenario-based NbS evaluation, comparing three distinct sequestration strategies to enable institutions to make informed choices to implement to achieve net-zero emissions by 2030 at the AIT campus. Further, firsthand data collection from approximately 2,000 tree measurements of carbon stocks in urban forest Thailand. Finally, by offering a replicable model for universities and similar institutions.

Comments 3: The article's structure should be presented at the end of the introduction.

Response 3: We thank the reviewer for this valuable comment. In response, we have removed the article structure to the end of the introduction accordingly.

Comments 4: The authors should highlight the research gaps by citing more recent articles and commenting on them to highlight the novelties of the present research.

Response 4: We thank the reviewer for this valuable comment. In response, we have highlighted the research gaps by citing more recent articles (paragraph 3) and commenting on them to highlight the novelties of the present research (paragraph 8)

Materials and Methods

This section is presented very well and in detail.

Results and discussion

This section is presented very well and in detail.

Policy implications

Comments 5: The author developed three scenarios; however, they only refer to scenario one in this section. Policy implications should rely on developed scenarios and the obtained results. Therefore, more policy implications are needed with a stronger connection to the developed scenarios.

Response 5: We thank the reviewer for this valuable comment. In response, we have revised the section “4.1 Strategic Implications for Net-Zero Goals” to include discussion of relying on each of Scenario to suggest the best option one.

Conclusions

Comment 6: The limitations of the present research should be mentioned here.

Response 6: We thank the reviewer for this valuable comment. In response, we have revised the Conclusion section to include study limitations.

Comments 7: Some recommendations for future research should be provided here.

Response 7: We thank the reviewer for this valuable comment. In response, we have revised the Conclusion section to also include suggestions for further research.

Comments 8: Also, the author should explain whether the obtained results answered the research questions and objectives of the present research provided in the introduction.

Response 7: We thank the reviewer for this valuable comment. In response, we have revised the Conclusion section to also include explaining that our study at the Asian Institute of Technology campus has made a substantial contribution to understanding the dynamics of carbon emissions and their sequestration. The results of the study effectively answered the research questions and objectives outlined in the introduction.

Reviewer 3 Report

Comments and Suggestions for Authors

This paper addresses an interesting issue, and it undoubtedly is fitting with the aims and scope of the journal. Also, it is of interest to the journal readers. The paper is based on a well-defined case study and its originality is good. The main ambition of the paper is basically empirical, i.e., there is no strong theoretical or conceptual contribution to be found. In general terms, I am favourable to this paper.

Even though the paper seems interesting, its contribution could be strengthened by a stronger framing of the issue: 

Very first, the lines 47-56 (the AIT) come to quickly, please move them to the paragraph starting from line 89. Further, the general aim of the paper is expressed in Introduction, but no major research question(s) is posed. Explicating the question(s) for the paper is a minor task, but it certainly helps to clarify the overall aim of the paper.

The introductory part also ignores the contexts of the knowledge. Since I suppose all readers are not basically very familiar with the Thai society, the interesting results from the case study tend to remain somewhat uncontextualised. This could be improved by introducing the Thai approach to climate policy and possibly also to climate policy instruments, for instance.

Further, from the title on, I assumed that ‘circular economy’ is a key concept in the paper. It is striking that the meaning of circular economy is neither defined nor discussed with the help of literature. The reader simply does not know whether it refers to its conceptual or practical meaning // to a concept, policy, strategy, practices, catchword or something else. This should be clarified.

The results are presented in a clear and thorough way. Yet, I must admit that I have no expertise on Thai land use and forestry, so I am not able to assess the empirical work and results in this respect. As a minor note: Lines 492-3 mention “high paper consumption”; yet, according to Table 6, the share of paper consumption re carbon emissions is very minor (roughly 0.7 %).

In Conclusion, it would be interesting to learn something more based on this Thai case study and, especially, what we can learn beyond this single (local) case. It would especially be interesting for the discussion if the author could share some of their thoughts on the principles and practices of the necessary upscaling. 

Regarding the language, the paper reads well.  

 

Author Response

We sincerely thank the reviewers and the editor for their valuable comments and constructive feedback, which have greatly contributed to improving the quality of our manuscript. We have carefully considered each suggestion and have made the necessary revisions to enhance the clarity, relevance, and impact of our study. We appreciate the time and effort invested in providing such insightful and detailed feedback.

We now address each comment in detail below.

Reviewer 3

Comments 1: This paper addresses an interesting issue, and it undoubtedly is fitting with the aims and scope of the journal. Also, it is of interest to the journal readers. The paper is based on a well-defined case study and its originality is good. The main ambition of the paper is basically empirical, i.e., there is no strong theoretical or conceptual contribution to be found. In general terms, I am favourable to this paper.

Response 1: We thank the reviewer for the positive feedback and for acknowledging the clarity and informative nature of our case study. We appreciate your valuable insights, and we have carefully addressed each of the minor points to improve the manuscript.

 

Even though the paper seems interesting, its contribution could be strengthened by a stronger framing of the issue:

 

Comments 2: Very first, the lines 47-56 (the AIT) come to quickly, please move them to the paragraph starting from line 89. Further, the general aim of the paper is expressed in Introduction, but no major research question(s) is posed. Explicating the question(s) for the paper is a minor task, but it certainly helps to clarify the overall aim of the paper.

Response 2: Thank you for this valuable suggestion. We agree with the comment and have removed them to the paragraph starting from line 89. Also, we have added majors questions as follows in paragraph 6: What are the current and projected baseline emissions at the AIT campus? What are the potential carbon stocks and removals from each nature-based solution? Which NbS scenarios can effectively achieve net-zero emissions on campus? And what strategic policy implications and lessons learned can be derived from scenario analyses to inform decision-making for net-zero pathways in small organizations and educational institutions?

 

Comments 3: The introductory part also ignores the contexts of the knowledge. Since I suppose all readers are not basically very familiar with the Thai society, the interesting results from the case study tend to remain somewhat uncontextualised. This could be improved by introducing the Thai approach to climate policy and possibly also to climate policy instruments, for instance.

Response 3: Thank you for this valuable suggestion. We agree with the comment and have added a brief introducing the Thai approach to climate policy and possibly also to climate policy instruments, for instance, from line 99-105.

Comments 4: Further, from the title on, I assumed that ‘circular economy’ is a key concept in the paper. It is striking that the meaning of circular economy is neither defined nor discussed with the help of literature. The reader simply does not know whether it refers to its conceptual or practical meaning // to a concept, policy, strategy, practices, catchword or something else. This should be clarified.

Response 4: Thank you for this valuable suggestion. We agree with the comment and have added a brief introduction of the concept of circular economy in the introduction, from line 64-71.

Comments 5: The results are presented in a clear and thorough way. Yet, I must admit that I have no expertise on Thai land use and forestry, so I am not able to assess the empirical work and results in this respect. As a minor note: Lines 492-3 mention “high paper consumption”; yet, according to Table 6, the share of paper consumption re carbon emissions is very minor (roughly 0.7 %).

Response 4: Thank you for this valuable suggestion. We agree with the comment and have removed sentence “Additionally, AIT experiences high paper consumption, which further adds to its carbon footprint. These factors indicate a potential area for implementing behavioral changes aimed at reducing emissions.” From the document.

Comment 5: In Conclusion, it would be interesting to learn something more based on this Thai case study and, especially, what we can learn beyond this single (local) case. It would especially be interesting for the discussion if the author could share some of their thoughts on the principles and practices of the necessary upscaling.

Response 5: Thank you for this insightful comment. We agree that expanding the conclusion to highlight broader implications and lessons learned beyond this local case study would enhance the impact of our findings. In response, we have revised the Conclusion section, on Lines 340-355, to emphasize the crucial roles of nature-based solutions (NbS) and circular economy practices, such as urban forest management, strategic species selection, and biochar application, in achieving net-zero emissions while enhancing biodiversity and ecosystem resilience. We also highlighted the adaptability and scalability of these strategies in diverse urban contexts, emphasizing the importance of strategic policy integration, stakeholder engagement, and capacity building to align localized actions with global sustainability goals.

Additionally, we discussed the multifunctional benefits of circular economy practices, including nutrient recycling and enhanced ecosystem productivity. The revised conclusion acknowledges challenges such as resource constraints, policy barriers, and monitoring needs while suggesting innovative approaches, cross-sector collaboration, and adaptive governance to overcome them. It also emphasizes the role of educational institutions in fostering environmental stewardship and climate literacy. This enhanced conclusion contextualizes the findings within the Thai setting while demonstrating the scalability and replicability of NbS strategies for urban sustainability transitions. If needed, we are open to further revisions.

 

Comment: Regarding the language, the paper reads well. 

Response: Thank you for your compliment.

 

Thank you very much for your time and valuable comments.

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Good job

Reviewer 3 Report

Comments and Suggestions for Authors

Thank you for responding to my comments. In my view, the manuscript is now a valuable contribution to the journal.