Simulation of the Impacts of Sea-Level Rise on Coastal Ecosystems in Benin Using a Combined Approach of Machine Learning and the Sea Level Affecting Marshes Model

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The main issue of the work is the description of the method. Authors need to describe their approach better adding more details about the ML techniques.

I did not understand where paragraph 2.4 is needed or why is included.

Results are poorly described and section 3.1 is very general.

Also the title on the platform "Sea Level Rise impact based on Machine Learning and SLAMM model for modeling Greenhouse Gas Sequestration in Benin coastal ecosystems"
is not the same as the one in the manuscript "Sea Level Rise impact based on Machine Learning and SLAMM model for modeling Greenhouse Gas Sequestration in Benin coastal ecosystems"

I did not make extensive comments in the manuscript since the methodology description is poor and I can not evaluate the results or the conclusions"

I believe that the authors need to restructure the manuscript and add more information and resubmit 

Comments for author File: Comments.pdf

Author Response

All comments have been considered point by point and highlighted  within the text. Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

 ARTICLE REVIEW 

Title: Simulation of the impacts of Sea Level Rise on coastal ecosystems in Benin using a combined approach of machine learning and the Sea Level Affecting Marshes Model 

Journal: Sustainability (MDPI) 

General Comments: 

The paper presents a work that employs a unique combination of machine learning and the Sea Level Affecting Marshes Model (SLAMM) to explore the effects of Sea Level Rise (SLR) on coastal ecosystems in Benin. This innovative approach has the potential to enhance the accuracy of simulations and provides valuable insights into the interactions between SLR and coastal environments. While the methodology is commendably detailed, there is room for improvement in the presentation of results. Some aspects of the results section appear to resemble literature review outcomes rather than the in-depth analysis that is expected. Moreover, the discussion section seems to contain much of the study’s results description. Below are my specific comments, which aim at providing ways of improvements and helping to strengthen the clarity and impact of the paper. 

 Introduction 

L61: “According to (Anderson et al., 2018)” this form of in text citation is incorrect, 

L64-65: If the context of your text refers to drains, being affected (blocked) by rising water levels due to flooding or other causes, you might want to clarify the specific situation you are describing. 

L79: What is “ML” Standing for? 

L79-81: It looks like there might be a typo or missing words in your sentence 

L106-109: Please, clearly state the specific study objectives at this last paragraph of the introduction section, as it would help readers understand the purpose and focus of the research. 

L94-96: “In contrast, given the breadth of uncertainty, future global mean SLR scenarios are a typical technique to take into account various future circumstances and design response choices” consider revising this sentence for more clarity. 

 Methodology 

L117-118: The coordinates you provided are indeed missing the north/south (latitude) and east/west (longitude) information. 

L122: “a daily thermal amplitude” is this referring to the difference between the maximum and minimum temperatures recorded within a single day or the average daily temperature? 

L123: the citation (CEDEO, 2013) and reference at L148 (page 14) needs to be corrected: it should rather be CEDEAO, 2013 or ECOWAS, 2013 

L178-179: “wetland categories and sea-level rise, permitting only one category change per time step. A time step of 20 years was used in this study to simulate the period from 2021 to 2090,” does 

this mean that the outputs will be obtained for the years 2021, 2041, 2061, and 2081 within the specified period. If this is the case, the output for 2090 will not specifically provided by the model. 

L185: On which basis were the 10 categories considered? please provide more details on that. What are these 10 wetlands? List them please 

L186: “with definition of 23 categories” is this different from the 25 wetlands categories offer by the NWI in table 2 

L189: “obtained from the website https://www.earthdata.nasa.gov” Which DEM did you used from this website? NASA Earthdata Search provides access to a variety of Digital Elevation Models (DEMs) with different spatial resolutions and coverages. Some of the available DEMs include SRTM, ASTER, GMTED . 

Provide the resolution of the used DEM 

Consider provide the database name in addition to the website name: NASA Earthdata Search. The same applies to L201-202 

It would have been valuable to include visualizations of the three input data sets used in the SLAMM model for better clarity and understanding. 

L217-218: It seems like the sentence is not complete, consider revising 

Table 2: This table has not been referenced in the text, please called it in the text where necessary. Certain parameters shown in the table need to be further described to enhanced understanding. 

 Results 

Figure 2: To which specific analysis does Figure 2 correspond? 

L242 & L259: The reference to "erosion caused by flooding" requires further clarification. Since erosion and flooding are distinct phenomena that often interact, it would be beneficial to provide additional details regarding the specific flooding events being referred to and how they lead to erosion. 

Table 3: How do you explain that mangrove area change (decrease) predicted under SLR in 2090 can be smaller than those of 2030-2050-2070 when comparing to the initial coverage. 

Figure3: I would recommend zooming in on the specific region where significant changes are observed for all illustrations in this figure look similar. I understand that SLR projections under RCP 8.5_Upper Limit scenario were used for the simulations but no such information was provided in the study’s objective nor in the methodology. 

Figure 4: I guess this is not an outcome of your analysis but rather this input data for your model. As such, it should be shown in the methodological section and source of this information should be provided. 

 Discussion 

The discussion section appears to include a substantial amount of results description. It would be beneficial to shift the focus towards discussing the implications of the observed land-use changes and their identified impacts. Furthermore, consider highlighting innovations and delving into the limitations of the methods and data used. Furthermore, to enhance the discussion section, you might also compare your findings with those of previous studies conducted in the same area or neighboring coastal zones, underlining the consistency of the current outcomes. 

 Conclusions 

P13, L112-113: This study rather demonstrates the suitability of the combination of SLAMM and ML 

Please provide recommendations for mitigating the adverse effects of flooding and erosion. This could involve suggesting strategies for coastal management, resource preservation, and sustainable development. 

Comments for author File: Comments.pdf

Comments on the Quality of English Language

any

Author Response

All comments have been considered point by point and highlighted within the text. Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

 

 COMMENTS ON THE REVISED MANUSCRIPT 

Title: Simulation of the impacts of Sea Level Rise on coastal ecosystems in Benin using a combined approach of machine learning and the Sea Level Affecting Marshes Model 

Journal: Sustainability (MDPI) 

General Comments: I appreciate the authors' efforts in addressing my previous comments and revising the manuscript accordingly. However, there are still some points that need to be addressed in order to further enhance the quality of the work. Below, you will find my comments on the revised manuscript: 

- Could you please clarify the rationale behind selecting only the RCP 8.5_Upper limit for this analysis? 

- The citation (CEDEO, 2013) and reference at page 19 line 219 needs to be corrected: it should rather be CEDEAO, 2013 or ECOWAS, 2013. 

- “In (Troll 1965) classification (1965)” must be corrected 

- “and it is inhabited by a population of 2.7 million people” It would be interesting to include the proportion of the 2.7 million people in relation to the national population, which would help assess the significance of this figure. 

- Why does the website format differ from the rest of the text, as seen in “Available at http://warrenpinnacle.com/prof/SLAMM6/'?” the same applies for “website https://www.earthdata.nasa.gov/.” 

- In Table 2, specifically in row 7, when you mention 'Historic Trend (mm/yr),' could you please clarify what you are referring to with “historic trend”? please avoid abbreviation of input parameters unless you describe them in the caption 

- In Figure 3, could you please specify the areas represented by the purple and blue boxes? It would be helpful to provide this information in the figure caption." 

- Figure 4, it would enhance clarity to maintain consistent border colors around each location. This will improve visual consistency. 

- In Figures 2, 3, and 4, consider using letters (e.g., A, B, C, ...) to differentiate between the illustrations within each figure. Additionally, provide detailed descriptions in the figure captions for better comprehension. 

- Regarding Figure 5, kindly indicate the source of the sea level projection presented in this figure. 

- On page 16, lines 42-43, where you mention, “This process causes an annual transport of 1,500,000 cubic meters of sand 42 from Lomé to Cotonou.” could you please provide key reference(s) to support this information? 

- Page 17- Line 122-123 “The erosion process leads to the emission of carbon into the atmosphere, generated by human activities and other sources.” Please provide more details and references to justify your statement 

- On Page 17, Lines-123-125 “Annually, approximately 500,000 individuals in West Africa face the peril of flooding and escalating coastal erosion, leading to substantial economic losses. Please provide references to support your statement 

 

 

- The statement “In 2013, these losses were estimated to account for 2.3% of Togo's 125 GDP, while in 2014, they amounted to 3.2% of Mauritania's GDP.” Need to be supported with key references 

- On page 18, Line 132-135: “Comparable circumstances are evident in Senegal, where annual floods impact approximately 133 200,000 individuals and generate an estimated average cost of $89 million per year. Particularly noteworthy are the exceptional floods experienced in 2009, which resulted in significantly higher damages totaling $104 million in Dakar”. Please, again support your sentences with key references. 

- Page 18, line 143: "One notable impact of sea level rise and droughts is the intrusion of saltwater." I do not see the necessity of discussing the effects of drought here. 

- The Conclusions section lacks mention of the reduction in carbon sequestration issue, despite it being one of the main objectives of this analysis. 

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 3

Reviewer 2 Report

Comments and Suggestions for Authors

Title: Simulation of the impacts of Sea Level Rise on coastal ecosystems in Benin using a combined approach of machine learning and the Sea Level Affecting Marshes Model Journal: Sustainability (MDPI) General Comments:

 

Comment:

 

I have reviewed the revised version of the article, and I am pleased to confirm that the necessary corrections have been incorporated. However, I would like to invite the authors to provide a context for the proposed recommendations. Including a short contextual statement will reinforce the link between the research findings and the proposed measures. Moreover, the added references (intext), such as Rattan et al., WACA ResIP-CCA, 2018, Croitoru et al. 2019, and World Bank, 2017, are absent from the references list. Additionally, I recommend that Table 3 be restructured for better readability.

Author Response

Responses

Q1: I would like to invite the authors to provide a context for the proposed recommendations. Including a short contextual statement will reinforce the link between the research findings and the proposed measures.

R1: The recommendations have been revised as you recommended

Q2: Moreover, the added references (intext), such as Rattan et al., WACA ResIP-CCA, 2018, Croitoru et al. 2019, and World Bank, 2017, are absent from the references list.

R2: References have been added

Q3: Additionally, I recommend that Table 3 be restructured for better readability.

R3: Table 3 has been restructured