A Scenario Simulation Method for Regional Sustainability Coupled with SD and Emergy: Implications for Liaoning Province, China

Round 1

Reviewer 1 Report

The paper is devoted to the study of the possibility of sustainable development of the territory on the example of a large industrial agglomeration. The paper explores the sustainable development path of the eco-logical economic system in Liaoning Province by establishing an emergy evaluation index system for evaluation on the basis of the development. Also, the paper introduces the system of the emergency assessment index into the system dynamics and establishes various development scenarios for assessing and predicting the state of sustainable development and the trend of the ecological economy against the backdrop of urbanization. This will allow, by comparing with the corresponding indicators in the simulation results, to correct the problems that exist in the development in a timely manner. Using system dynamics and emergy theory to construct four scenarios for the development of the ecological economic system in Liaoning Province, the authors used the Vensim software to create a corresponding system dynamics model. Based on the simulation, the authors made a number of conclusions and suggestions.

There is no explanation why in Figures 5-13 the y-axis values for 2017 and 2018 are so different.

The text contains the messages “Error! Reference source not found"

Author Response

Dear Reviewer:

Thank you for your comments concerning our manuscript entitled “A Scenario Simulation Method for Regional Sustainability Coupled with SD and Emergy：Implications for Liaoning Province，China”. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. Revised portions are marked in red in revised manuscript (changes marked). Our point-to-point responses to your comments, which are highlighted in italic, are presented below.

Responds to the reviewer’s comments:

1.There is no explanation why in Figures 5-13 the y-axis values for 2017 and 2018 are so different.

Response: Thanks for your review. In Figure 5，the indicator EDR is used to measure the emergy required for the unit GDP. The GDP before 2020 is the real value. The GDP growth rates of Liaoning Province in 2017 and 2018 are 4.2% and 5.8% respectively, which is significantly different from the growth rate of 0.9% in 2020. In addition, we corrected some missing data，the GDP growth trend after 2020 is estimated.

“The selected parameters are primary, secondary and tertiary industries investment co-efficients and the level of technological progress, proportion of imports and exports, Comprehensive utilization rate of solid waste and wastewater treatment rate. And ac-cording to documents related to the "14th Five-Year Plan" of Liaoning Province and city-related construction, parameter settings based on existing data are shown in Table 4. Then the dynamic simulation of the development mode from 2017 to 2035 is carried out to analyze the simulation results”. At the time of data collection, we clarified that some missing data in 2017 would lead to a large difference from the results in 2018. 

2. The text contains the messages “Error! Reference source not found"

Response: According to your advice, we have made corrections to the references. We have deleted non-existing references, ensured accuracy of bibliographic references. The deleted references are as follows:

1. Ma Wenjing & Liu Juan. (2020). Evaluation of sustainable development of China's ecological economic system based on emergy analysis. Chinese Journal of Applied Ecology (06), 2029-2038. doi:10.13287/j.1001-9332.202006.038.
2. Odum, H. T. (1988). Self-organization, transformity, and information. Science,242(4882),1132-1139
3. Tan, C.C., Lv, J.H., (2012). Scenario prediction of the energy value of ecological economic system in Heilongjiang Province. Forestry Economy (04), 39-42.
4. Wang, W.Guo, X.J., (2019). Evaluation of Sustainable Development of Ecological Economic System in Shanxi Province Based on Emergy Analysis. Journal of Shanxi Normal University (Natural Science Edition) (04), 61-67.

Author Response File: Author Response.pdf

Reviewer 2 Report

Title: A Scenario Simulation Method for Regional Sustainability Coupled with SD and Emergy：Implications for Liaoning Province，China

The article appears to be interesting but is necessary implement convincingly some procedural aspects to be published.

Paragraph Emergy flow chart

It is absolutely necessary to present a description of the breakdown for each component that analysed   social, economic and ecological aspects in the Liaoning Province.  Then, explain how each component has been translate in an equivalent solar energy system in order to perform the “emergy analysis” prodorme Oum (Odum, 1996; Brown and Herenden, 1996; Brown and Ulgiati, 1997; Brown and Buranakarn, 2003).

In the description of the Table 1 it is necessary to mention that sej is solar emjoules

Functions 7 and 8 in the Cobb/ Douglas production function A(t) level of technological progress. please describe how you have measured this component in the Liaoning Province.

In the Scenario Setting paragraph please explain which parameters you have chosen to perform the current scenario, economic priority type and the environmental priority type. Please explain the used variables in the model and how to arrive to the coefficient in the table 4

Please mention Vensim Software not in the conclusions but in the Methodology.

Author Response

Dear Reviewer:

Thank you for your comments concerning our manuscript entitled “A Scenario Simulation Method for Regional Sustainability Coupled with SD and Emergy：Implications for Liaoning Province，China”. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. Revised portions are marked in red in revised manuscript (changes marked). Our point-to-point responses to your comments, which are highlighted in italic, are presented below.

Responds to the reviewer’s comments:

1, Paragraph Emergy flow chart

Response: Thanks for your review. Emergy flow map of ecological and economic system in Liaoning Province is shown in Figure 1. “The eco-economic system is composed of three subsystems: social, economic and environmental, and the interaction among input, output stream and system components. Input of renewable resources such as sun, wind, rainwater and non-renewable resources such as coal in the environmental subsystem, the purchased emergy of the economic subsystems such as goods, services, and the two are input into the social subsystem through the flow of emergy. The social subsystem realizes the transformation of emergy in different products, and returns the transformed waste emergy to the environmental subsystem. The economic subsystem provides capital security for the other two systems through feedback input, and the three complement each other.” 

2.It is absolutely necessary to present a description of the breakdown for each component that analysed social, economic and ecological aspects in the Liaoning Province. Then, explain how each component has been translate in an equivalent solar energy system in order to perform the “emergy analysis” prodorme Oum (Odum, 1996; Brown and Herenden, 1996; Brown and Ulgiati, 1997; Brown and Buranakarn, 2003).

Response: Thanks for your advice, we have added the specific statement of the three subsystems of society, economy and ecology in Liaoning Province and the mechanism of mutual emergy transformation. As follows:

“The eco-economic system in Figure 1 is composed of three subsystems: social, eco-nomic and environmental, and the interaction among input, output stream and system components. Input of renewable resources such as sun, wind, rainwater and non-renewable resources such as coal in the environmental subsystem, the purchased emergy of the economic subsystems such as goods, services, and the two are input into the social subsystem through the flow of emergy. The social subsystem realizes the transformation of emergy in different products, and returns the transformed waste emergy to the environmental subsystem. The economic subsystem provides capital security for the other two systems through feedback input, and the three complement each other.” 

3.In the description of the Table 1 it is necessary tomention that sej is solar emjoules

Response: According to your comment, we have added the statement that sej is the solar emjouers to the previous concept statement.

Solar emergy is the amount of solar energy contained in any flowing or stored energy, its unit is solar emjouers (sej). 

4. Functions 7 and 8 in the Cobb/ Douglas production function A(t) level of technological progress. please describe how you have measured this component in the Liaoning Province.

Response: According to the equation (7) and (8), this paper calculates the scientific and technological progress coefficient of Liaoning Province from 2010 to 2017 by fitting the known total industrial output value, labor force population, fixed asset investment, and labor and capital elasticity coefficients of Liaoning Province. 

5. In the Scenario Setting paragraph please explain which parameters you have chosen to perform the current scenario, economic priority type and the environmental priority type. Please explain the used variables in the model and how to arrive to the coefficient in the table 4.

Response: Thanks for your review. We modified “3.3. Scenario settings”, and added “3.3.1 Development mode setting” and “3.3.2 selection of scenario parameters”

In “3.3.1 Development mode setting”, the setting of the scene parameters is based on the following:

“Current mode: All parameters are the current values of the system.

Economic Priority Type: Taking economic maximization as the standard, focus on increasing the investment coefficient and technological progress coefficient in the secondary industry, reducing the investment coefficient in the tertiary industry, and reducing the import and export ratio. Due to the serious waste pollution caused by the economic priority type, its comprehensive waste utilization rate and wastewater treatment rate will decrease.

Environmental priority: Based on the maximum environmental protection, reduce the investment coefficient of the primary and secondary industries, increase the investment coefficient and progress level of the tertiary industry, adjust the import and export ratio, and improve the comprehensive utilization rate of solid waste and wastewater treatment rate.

  Coordinated development type: Take the approximate balance of economic priority type and environmental development type, and strive to maximize economic and environmental benefits.”

In “3.3.2 selection of scenario parameters”, we further elaborated the process of parameter selection.

“The selected parameters are primary, secondary and tertiary industries investment coefficients and the level of technological progress, proportion of imports and exports, Comprehensive utilization rate of solid waste and wastewater treatment rate. The se-lection of scenario parameters is mainly to select the important factors that affect the social, economic and environmental development of the system, and the economic development involves internal circulation and external circulation. The proportion of in-vestment in the primary, secondary and tertiary industries in the internal circulation and technological progress have different impacts on it. For example, the increase in investment in the primary and secondary industries will lead to rapid economic and social development and rapid GDP growth. However, due to the serious environmental pollution it brings, the economy cannot be developed blindly. Therefore, it is necessary to seek a balance of investment in the tertiary industry. According to the factors affecting the development of GDP, this paper also selected the parameter of the coefficient of scientific and technological progress. The progress of science and technology will also make the society progress, the economy develops more healthily, and the pollution to the environment will also be reduced. External circulation is mainly measured by the index of domestic and foreign imports and exports. Finally, the most intuitive indicators that can show the reduction of environmental pollution are the comprehensive utilization rate of solid waste and the rate of wastewater treatment, which is also one of the obvious causes of urban pollution.

Comparing these indicators, the results can provide better reference results for the sustainable development of society, economy and environment. And according to documents related to the "14th Five-Year Plan" of Liaoning Province and city-related construction, parameter settings based on existing data are shown in Table 4. Then the dynamic simulation of the development mode from 2017 to 2035 is carried out to analyze the simulation results.”  

5. Please mention Vensim Software not in the conclusions but in the Methodology.

Response: Thank you for your suggestion, we have added the introduction of the Vensim software in the methodology and deleted the description in the results

“Vensim is a system dynamics software that enables high-quality dynamic feed-back models by building dynamic models and understanding the causal relationship diagrams of various variables in the system. In this paper, the emergy theory and system dynamics are combined to simulate and analyze the development of the ecological economic system in Liaoning Province.”

 Author Response File: Author Response.pdf

Reviewer 3 Report

The presentation reflects the present state of knowledge. The paper is very well structured. The Introduction section is good, in this section the authors present clearly the objectives and the main contributions of the study. The authors provided sufficient background and include relevant references. The research design is innovative and appropriate. The results are clearly presented. The conclusions are supported by the results. 

Author Response

Dear Reviewer:

Thank you for your comments concerning our manuscript entitled “A Scenario Simulation Method for Regional Sustainability Coupled with SD and Emergy：Implications for Liaoning Province，China”. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. Revised portions are marked in red in revised manuscript (changes marked). 

Thank you for your affirmation of the paper. Your comments are an encouragement to our paper writing. We are fully aware that there is still a long way to go in the subject research, and we will exert our utmost effort to complete the future research.

Author Response File: Author Response.pdf

Reviewer 4 Report

From the perspective of eco-economic system, this research couples SD and emergy methods to conduct scenario simulation research. However, there are still many problems as follows:

1)     The introduction part of the literature review lacks summary and comment, which lists many previous studies, but does not find the research gaps. For example, the introduction mentioned that the emergy analysis is a static evaluation analysis method, which cannot be used for dynamic analysis. Therefore, emergy and SD are combined to conduct the scenario simulation research. In fact, many previous studies have done this, which does not make up for the research gaps. Therefore, the innovation of this study is not clearly pointed out.

2)     The introduction of the calculation of subsystem is very detailed, but the calculation of each index of the emergy calculation is not clarified (Table 2), just the results are directly given. It is suggested to refine the calculation process of emergy analysis.

3)     The results obtained under different scenarios are similar, and 2017-2020 shows dramatic changes in some indexes, but the subsequent years show a very single trend. This means that the result is unreasonable. Among them, there must be problems of methods, ideas or data. Perhaps the model setting of system dynamics is not scientific.

4)     There are many text format errors in the manuscript, which need to be carefully checked.

Author Response

Dear Reviewer:

Thank you for your comments concerning our manuscript entitled “A Scenario Simulation Method for Regional Sustainability Coupled with SD and Emergy：Implications for Liaoning Province，China”. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. Revised portions are marked in red in revised manuscript (changes marked). Our point-to-point responses to your comments, which are highlighted in italic, are presented below.

Responds to the reviewer’s comments:

1.The introduction part of the literature review lacks summary and comment, which lists many previous studies, but does not find the research gaps. For example, the introduction mentioned that the emergy analysis is a static evaluation analysis method, which cannot be used for dynamic analysis. Therefore, emergy and SD are combined to conduct the scenario simulation research. In fact, many previous studies have done this, which does not make up for the research gaps. Therefore, the innovation of this study is not clearly pointed out.

Response: According to your comment, we have added a research gap narrative that clearly identifies the innovations of this paper.

“In general, the combination of emergy analysis and system dynamics can better simulate the development of the system from quantitative and qualitative aspects, dynamic and static aspects. But the number of studies combining the two is still a small number, and most of them focus on agriculture, economy, environmental protection and other individual fields or city level, there is a lack of research on the whole society, economy, ecosystem, and research on a larger spatial scale (such as the provincial level)”. Therefore, this paper can study the whole ecological economic system of Liaoning Province from this perspective to make up for the lack of research literature. 

2. The introduction of the calculation of subsystem is very detailed, but the calculation of each index of the emergy calculation is not clarified (Table 2), just the results are directly given. It is suggested to refine the calculation process of emergy analysis.

Response: Thanks for your advice, we have added the specific formula for the conversion of material energy value in the text, which is conducive to better understanding. As follows:

“1. Collect the original data among various elements and related components in the ecological economic system of Liaoning Province, then calculate the energy of different substances: E.

2. Determine the corresponding emergy transformity of each substance: T.
3. Calculate the solar emjouers : .“ 

3. The results obtained under different scenarios are similar, and 2017-2020 shows dramatic changes in some indexes, but the subsequent years show a very single trend. This means that the result is unreasonable. Among them, there must be problems of methods, ideas or data. Perhaps the model setting of system dynamics is not scientific.

Response: Thank you for your comment. Since the data for 2017-2020 are the real data, the simulated results also belong to actual fluctuations. However, the data after 2020 is the result of forecasting based on the trend simulated by the data of historical years. System dynamics is suitable for dealing with complex socio-economic problems, the relationship and function between the elements of the system are simulated by computer modeling, and the change trend of the system is dynamically analyzed. In the introduction, we added the relevant literatures on the application of system dynamics. The literatures are also based on a trend simulation of the future. Using system dynamics to make accurate predictions is also a direction we can study in the future. 

4. There are many text format errors in the manuscript, which need to be carefully checked.

Response: According to your comment, we have carefully checked the article with reference to the sample text format. The corrections made are as follows:

1. We have corrected the reference method of the literature, which is expressed in red font in the text.
2. We have corrected the column points in the text with numbers 1, 2, 3, etc.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The key aspects have been clarified. The article deserves to be published!

Author Response

Thanks for your review. Our manuscript has been checked and polished by an English speaking colleague.

Author Response File: Author Response.pdf

Reviewer 4 Report

The manuscript has indeed made some revisions, but there are still the following problems:

1. The basis of setting of simulation parameters needs to be further explained to increase the practical significance of simulation;

2. The system dynamics model itself does have the problems mentioned before, so that the simulation results tend to continuously increase or decrease. The paper lacks a "discussion" chapter. If possible, it is suggested to add a discussion chapter to put forward policy suggestions and discuss the contributions and limitations of this study; 

3. Some of the simulation results are not fully explained, and some of the results are unreasonable. For example, "the epidemic and Sino-US trade frictions are the reasons hindering the speed of economic development" The epidemic and Sino-US trade frictions are all unexpected events and the future is unknown. How can we draw such conclusions? Why is “the coordinated development type economy develops the fastest”? Why is the GDP of the economic priority type not always the highest?

Author Response

Dear Reviewers:

Thank you for your comments concerning our manuscript entitled “A Scenario Simulation Method for Regional Sustainability Coupled with SD and Emergy：Implications for Liaoning Province，China”. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. Revised portions are marked in red in revised manuscript (changes marked). Our point-to-point responses to your comments, which are highlighted in italic, are presented below.

Responds to the reviewer’s comments:

Reviewer #4:

1. The basis of setting of simulation parameters needs to be further explained to increase the practical significance of simulation;

Response: According to your suggestion, we have added a description of the categorization of parameters at Table 4 to better represent the practical implications of parameter selection. We also provide a detailed description of the breakdown and meaning of the data. As follows:

   “Selection of scenario parameters is to comprehensively analyze the impact of development paths, industrial layout, technology levels, economic development and environmental protection policies on the sustainable development of the eco-economic system in Liaoning Province, while taking into account the relevant planning requirements of Liaoning Province. The selected parameters are primary, secondary and tertiary industries investment coefficients and the level of technological progress, proportion of imports and exports, comprehensive utilization rate of solid waste and wastewater treatment rate. The industrial layout is represented by the investment coefficients of the three industries, and the level of science and technology measured by the Cobb Douglas function, see equation (5). The proportion of imports and exports is related to GDP, and the ratio of the two is used to express the impact of external circulation on the economy system. And the comprehensive solid waste utilization rate and wastewater treatment rate are set according to environmental policies. The overall indicators are selected and adjusted according to the SD model established.”

2. The system dynamics model itself does have the problems mentioned before, so that the simulation results tend to continuously increase or decrease. The paper lacks a "discussion" chapter. If possible, it is suggested to add a discussion chapter to put forward policy suggestions and discuss the contributions and limitations of this study;

Response: Thank you for your suggestion，we have added a "Discussion" section to this paper, mainly to elaborate on the policy suggestions for this research, as well as its contributions and limitations. Details as follows:

     “4.1 Policy suggestions

The energy value analysis of Liaoning's eco-economic system reveals a non-sustainable economic development. As Liaoning is a heavy industrial base, it relies mostly on imported resources, resulting in a greater energy value of inputs than outputs, while emerging national debt yields continue to fall, so the ESI shows a downward trend, with relatively large environmental load rates, low levels of technology and serious waste pollution. Therefore, it is necessary to continuously expand the utilization rate of renewable resources, adjust the ratio of imports and exports, and improve the technological content for its optimal direction. Suggestions to policy makers are as fol-lows.

1. Optimize the industrial layout and adjust the structure of resource utilization. In terms of economic circulation, Liaoning Province should increase fixed asset investment in the tertiary industry, reduce fixed asset investment in the heavily polluted primary and secondary industries, and focus on the coordinated development of the leading industry manufacturing and productive service industries. At the same time, reduce the brain drain, increase funding for technological innovation in the three major industries, and set up superior salaries, benefits and household registration to attract relevant talents to settle in the province. In addition, through technological innovation, Liaoning Province should focus on the development of renewable resources such as solar energy value and wind energy, reduce the reliance on and use of non-renewable resources, improve resource utilization and ease the pressure of resource depletion. In terms of the external circulation of the economy, Liaoning Province should will adjust the proportion of imports and exports, increase exports, reduce the proportion of imports and dependence on foreign investment. Invest in the development of a "circular economy", improve resource utilization, integrate cleaner production and focus on building an infrastructure for resource optimization.
2. Increase investment in environmental protection technology to improve waste utilization. As a heavy industrial base, Liaoning Province has, over the years, accumulated a large number of environmental pollution problems from the discharge of industrial waste, leading to the hindrance of its ecological civilization. According to the national emergency energy saving and emission reduction requirements, the revitalization of the old industrial base is combined with scenarios with sustainable development related parameters and emphasis on public infrastructure construction. For ex-ample, the construction of eco-industrial parks uses sewage treatment systems for water reuse and public sewage treatment facilities to improve the level of resource utilization and waste recycling. This approach can improve the efficiency of waste con-version, facilitate its maximization of power output, reduce emergent consumption, improve environmental quality and seek a low-carbon development path.
3. Increase the proportion of high-tech investment and strengthen scientific and technological innovation. Scientific and technological progress can bring about progress in productivity and promote economic development. Liaoning Province should improve the utility of high-tech talent, promote the development of high-tech industries, build industrial innovation platforms, and develop relevant policies to promote industrial innovation. It should also strengthen scientific and technological exchanges and infrastructure, unite regional universities to cultivate dovetailing talents in the sustainable development of the ecological economy, and set up corresponding innovation driven funds to enhance innovation strength.

4.2 Contribution and limitations

The combination of the emergy analysis method and the system dynamics method provides a new research idea for the sustainable development of ecological and economic systems, makes up for the shortcomings of a single research method and provides a reference for the study of ecological and economic systems in the provincial space. On the basis of implementing the national concept of green development, this study is a guide to the implementation of the old industrial base of Liaoning in practising the concept of ecological priority and green development and environmental protection. It will help Liaoning Province further define the direction and focus of green and sustainable development, and also facilitate the exchange of valuable opinions with other cities in similar development situations, so that making better suggestions can be to achieve sustainable development.

Due to the differences in methodology between the two studies, there are a number of limitations to the adaptation study. Firstly, there are differences in the selection of emergy transformation rates. The energy conversion rates here are taken from existing studies, but their applicability cannot be fully guaranteed due to the heterogeneity of the study object. Secondly, for the scientific accuracy of the energy value data, the data here are obtained from different sources and the system dynamics requires a large amount of data to support the results, which may lead to uncertainty and validity, thus affecting the simulation results and the conclusions accordingly.”

3. Some of the simulation results are not fully explained, and some of the results are unreasonable. For example, "the epidemic and Sino-US trade frictions are the reasons hindering the speed of economic development" The epidemic and Sino-US trade frictions are all unexpected events and the future is unknown. How can we draw such conclusions? Why is “the coordinated development type economy develops the fastest”? Why is the GDP of the economic priority type not always the highest?

Response: Thank you for your comments. we have added the corresponding explanation in the text. For the first question, the point of this paper is that the slow growth rate of the economy until 2023 could be due to the impact of the epidemic and Sino-US trade frictions. “Sino-US trade frictions gradually intensify after 2018 until they largely ease in early 2022. The epidemic, which broke out in late 2019, is still present, but the situation is much less severe than before. During this period, the two pairs have largely influenced the pace of economic development. On the basis of current trends, this paper predicts that in the future, the easing of the situation between the two will mitigate the impact on the economy. The coordinated development type economy will be the fastest, the production capacity will be the strongest, and the system development will be the most dynamic.”

For the second question, because “In an eco-economic system, economic development is closely related to society and the environment, a single-minded approach to economic development leads to a deterioration in the relationship between society and the environment, which in turn inhibits economic development. On the contrary, in the coordinated development type, the improvement of the environmental situation and the coordination of social development in turn has a catalytic effect on economic development, increasing the sustainable socio-economic development. Therefore, it is possible for the coordinated development type of economic development to outperform the economic development type.”

Author Response File: Author Response.pdf

Round 3

Reviewer 4 Report

No.