PCLM-D-22-00098

Climate change scenario projections and their implications on food systems in Taita Taveta County, Kenya

PLOS Climate

Dear Dr. Nyambariga

Thank you for submitting your manuscript to PLOS Climate. After careful consideration, we feel that it has merit but does not fully meet PLOS Climate’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by 24 December 2022. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at climate@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pclm/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

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• A rebuttal letter that responds to each point raised by the editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
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• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

We look forward to receiving your revised manuscript.

Kind regards,

Noureddine Benkeblia, Dr. Sci., Dr. Agr.

Academic Editor

PLOS Climate

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Additional Editor Comments (if provided):

Dear Dr. Nyambariga,

Your manuscript was reviewed and the final decision reached is: MAJOR REVISION.

When revising your manuscript, please consider all issues mentioned in the reviewers' comments carefully: please outline every change made in response to their comments and provide suitable rebuttals for any comments not addressed. Please note that your revised submission may need to be re-reviewed.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Does this manuscript meet PLOS Climate’s publication criteria? Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe methodologically and ethically rigorous research with conclusions that are appropriately drawn based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available (please refer to the Data Availability Statement at the start of the manuscript PDF file)?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception. The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

Reviewer #2: Yes

Reviewer #3: Yes

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS Climate does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The manuscript reads like a thesis report. The effects of climate changes based on 2 emission scenarios RCP4.5 and RCP8.5 pathways on food production and its socio-economic implications in Taita Taveta County, Kenya are presented.

The projected effect on agriculture and other sectors such as health, tourism and economic sectors are listed in Table 4 but there is no explanation how these results are derived. These projected effects are qualitatively assessed. Considering these results are the aim of the study, they are not well explained and derived. The supplementary materials contains survey questionnaire but there is no mention of this survey in the main manuscript. Are this survey results used in this study ?. The projected climate data used is probably CMIP5 used in CORDEX-Africa and this CMIP version should be mentioned in the manuscript.

On the structure and contents of the manuscript, the introduction is too long while the discussion is too short. Some of the introduction should be in the discussion and related to the results of this work. In the method section, Mann-Kendall test should be shortened rather explained in detail as this test is well known. Many acronyms were used but they should be in full names when they are first used.

Overall the approach and methods used are reasonable and standard. Only the presentation needs to be restructured. I recommend the manuscript to be revised.

Some specific comments:

(1) In Introduction section, paragraph 3: Full name of IGAD (in addition to the acronym) should be specified when mentioned first time. Similarly IPAC should have full name. And many others in the manuscript, such as Regional Climate Models (RCMs). .

(2) In Mann Kendall trend test section, you don't need to explain in detail this well-know non parametric trend test.

And "...how close the patterns march the observed..." should be "... how close the patterns match the observed..."

(3) Table numbering is wrong: There are no such table 5, 6. And table 4 is Table 7 in the supplementary materials.

Reviewer #2: Most of my comments are in my attachment. However, it is a well written paper with some insightful data . This is a very timely and relevant work especially from the perspective of a lack of climate data to inform agricultural decision making in many African countries.

Reviewer #3: The authors take on a critically important topic of how climate projections for the rest of the 21st century will impact food production and security in a southern province in Kenya. They are thorough in employing different models to create scenarios of climate change, comparing those model outputs to each other, and cross-validating model results with instrumental measurements to evaluate the best performing models. The concept, approach, need for the work, and background information is well-written and communicated in the first half of the manuscript. I would like to see this work published in a journal like PLOS Climate, though the manuscript does need substantial work first.

Where this paper needs major revisions are 1) correcting formatting and punctuation issues throughout the entire manuscript, 2) poor organization and writing in the second half of the paper ("Results and Discussions"), 3) several mistakes with labeled and numbering tables and figures, and 4) a disconnect between statistical analyses chosen and the interpretive discussion on precipitation variability. I discuss each of these points below.

1) Formatting issues throughout manuscript

The authors did not follow PLOS Climate guidelines to have a system of headers and subtitles that were consistently formatted throughout the manuscript. The start out with (1) Introduction and (2) Materials and Methods, but then have another (2) Data Used in the Study. Then the numbering stops altogether for the middle of the manuscript. I would suggest renumbering headers and noting subheaders consistently, e.g. 1, 2.1, 2.2, 3.1 etc.

Be sure to leave a space between any number communicated in the text and its unit of measurement. For example "60 mm" and not "60mm." Use superscript for the "2" in km2.

There is inconsistent capitalization throughout, e.g. "county" or "County" to refer to the study region of Taita Taveta, some sentences start with a lowercase letter, there were instances of "table 3" when it should have been capitalized. Proofread carefully.

Take out any semicolon punctuation in the manuscript and rephrase the sentence, or reformat it to be 2 sentences. Semicolons make for awkward syntax in most scientific writing, and authors did not use them properly in any case.

Finally, at the end of "Methods and Materials," there seems to be a list that got improperly embedded in the format of the manuscript. ("1. Coeff of variantion, 2. This is a statistical measure...") This did not make sense as a list at all, and seemed it should have been in paragraph form.

2) and 3) Poor Organization and Writing especially in "Result and Discussions" and "Conclusions"

The writing in the first half of the manuscript mostly flowed well, was clear, and paragraphs had clear topics and intent to them. The second half of the manuscript was a lot harder to follow, with many more grammar and formatting mistakes. It also jumped from objective reporting of results to interpretation, which was difficult to follow.

I would first suggest the authors have a clear "Results" section (labeled as 3. Results), where they report objective results and present their figures. Then a separate "4. Discussion" or "4. Interpretation" section that discuss the implications, and have their "Projected Impacts of Climate Change on Food Systems" table. The paper would be stronger if the authors addressed in the text which items in that "Projected Impacts" table will be of greatest concern to the Taita Taveta region, based on its terrain, prevailing climate, and study results.

Next, the figures and tables were numbered and labeled incorrectly. The order of tables in the manuscript goes, Table 1, Table 2, Table 1, Table 2, Table 3... There were also two "Figure 1" labels. This means the references in the text to these figures did not match at all. It was confusing to follow, especially in the Discussion when figures that had come before were referenced again.

For Table 1 (or is it supposed to be Table 3?) "Observed trends for annual rainfall..." the caption mentions that bold values should stand out, but my copy did not show any bold at all. So, this information was lost in the formatting.

The "Conclusions" would be stronger if it reiterated which "Projected Impacts" are of specific concern to the region, based on the warming trend observed, its unique topography, and variability. Which ones are the most critical for adaptation and mitigation? Being specific here would speak more clearly and accessibly to a wider audience, and policymakers.

4) No robust measure or description of projected rainfall variability

The authors are clear and thorough in their description of methods for model comparison, and statistical analysis that were chosen and how these were carried out. In their reporting of the precipitation results, they note minor increases and show trend lines and best fit lines on their graphs. Indeed, their statistical analyses do not seem to assess more than *broad* trends over time.

This leaves the reader wondering how they could better assess and describe the changes in precipitation *variability* in their scenario results. Indeed, the manuscript early on provides background on how important the seasonality of rainfall is to agriculture and the growing season. In the "Discussion," the rainfall variability is mentioned only in vague terms.

This creates a large disconnect between precipitation results, where the authors report "positive shift in the total annual rainfall" and "trends were not statistically significant for rainfall." They then jump to an interpretive discussion of variability, without much substance on *how* variation will change over time. Is there a particular year or inflection point where amplitude increases? How does this impact the current rainy seasons crops depend on? I believe all readers will know that wetter/dryer extremes negatively impact agriculture, but a more robust measure and discussion of HOW, WHERE and WHEN this variability will express would make the study stronger.

Discussions of projected climate variability and how this is assessed is abundant in the literature, as climate extremes are expected in many other regions of the world. Two well-known studies I am the most familiar and would suggest come from California, another important agricultural region. These studies use terms like "climate erraticism" (Loisel et al., 2017) and "climate whiplash" (Swain et al., 2018) to describe this increased variability, and are very specific on how they measured and assessed this phenomenon.

Loisel J, MacDonald GM, Thomson MJ. Little Ice Age climatic erraticism as an analogue for future enhanced hydroclimatic variability across the American Southwest. PloS one. 2017 Oct 16;12(10):e0186282.

Swain DL, Langenbrunner B, Neelin JD, Hall A. Increasing precipitation volatility in twenty-first-century California. Nature Climate Change. 2018 May;8(5):427-33.

I would suggest the authors look at these and other examples in the literature to help strengthen their assessment and discussion of precipitation variability projections for Taita Taveta County, Kenya.

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6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

Do you want your identity to be public for this peer review? If you choose “no”, your identity will remain anonymous but your review may still be made public.

For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: Yes: Hiep Duc Nguyen

Reviewer #2: Yes: Bob Offei Manteaw PhD

Reviewer #3: No

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[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

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Attachments

Attachment

Submitted filename: Plos_Climate_Review.docx

PCLM-D-22-00098R1

Climate change scenario projections and their implications on food systems in Taita Taveta County, Kenya

PLOS Climate

Dear Dr. Nyambariga,

Thank you for submitting your manuscript to PLOS Climate. After careful consideration, we feel that it has merit but does not fully meet PLOS Climate’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

==============================

After careful reviewing, the manuscript still requires consistent revision and comments of the reviewers should be addressed. Please outline in a cover letter every change made in response to their comments and provide suitable rebuttals for any comments not addressed.

==============================

Please submit your revised manuscript by 25 February 2023. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at climate@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pclm/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

We look forward to receiving your revised manuscript.

Kind regards,

Noureddine Benkeblia, Dr. Sci., Dr. Agr.

Academic Editor

PLOS Climate

Journal Requirements:

1. Please upload all main figures as separate Figure files in .tif or .eps format only and remove the embedded figures from the manuscript file. For more information about how to convert and format your figure files please see our guidelines: 

https://journals.plos.org/climate/s/figures

Additional Editor Comments (if provided):

After a careful reviewing, the manuscript still requires consistent revision. All the comments of the reviewers should be addressed. Please outline in a cover letter every change made in response to their comments and/or provide suitable rebuttals for any comments not addressed.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #3: (No Response)

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2. Does this manuscript meet PLOS Climate’s publication criteria? Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe methodologically and ethically rigorous research with conclusions that are appropriately drawn based on the data presented.

Reviewer #1: Yes

Reviewer #3: Partly

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #3: I don't know

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4. Have the authors made all data underlying the findings in their manuscript fully available (please refer to the Data Availability Statement at the start of the manuscript PDF file)?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception. The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #3: Yes

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS Climate does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #3: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Please check the numbering of Figures correctly. For example in the text, referring to Figure 4 as the Taylor diagram but Taylor diagram is actually in Figure 3.

Reviewer #3: Recommendations:

MAJOR ISSUES:

1) The Materials and Methods section was better organized and straightforward to read with the recommended changes. However, the authors present a dimension and set of methods to the study that was not in the original version: a series of household food surveys in the community. Integrating this into the manuscript raises a lot of questions and concerns at this stage. First, it is a vastly different methodology and type of study compared to climate modeling. It isn’t presented with the same robustness as the climate modeling. Are the questions included as an appendix? Was an I.R.B. required for this work? Second, I would expect figures and results of 100+ respondents to be presented in the “Results,” but there was no mention of results and insight in this section at all. Instead, impressions from the survey are mentioned rather anecdotally in the discussion. This survey component feels like it should be a separate study and manuscript.

There is no mention of this additional survey methodology and insight in the Abstract. In fact, the Abstract has hardly been revised. The Abstract would be improved if it mentioned concrete findings and policy recommendations. For example, specific examples of year and temperature results from the modeling (as we see in section 4.2) and food security items from Table 7 that are specifically under threat with future climate change.

2) While the climate modeling results are better organized, there was little change to the writing. In Section 3.2, it would be helpful to see results of monthly mean temperature and precipitation values in degrees C and mm at the beginning, or have this presented alongside the coefficients assessed. This would provide more meaning to statements like those below Figure 4. It is also not clear what units of measurement apply to the numbers referenced in statements below Table 4 about seasonal rainfall variability.

3) I previously recommended literature on climate erraticism and whiplash as examples for statistical approaches to better assess variability in their study region. In this revision, the authors have included the papers’ findings in the narrative. However, I find it has not added substance to the direct analysis and interpretation of their own data. The authors take the general implications of these papers (Swain et al., Loisel et al) - which include future risk of landslides, erosion, and wildfire specific to a mediterranean-type region - and apply them rather uncritically to their own study region. Using these papers briefly to highlight crop risk in a later section of the paper (Discussion) was more effective.

4) There is more substance to the Discussion section, but much of it is topically disorganized. This is especially true in pp. 28-32. The author’s photo of drought is a new addition and would probably be more compelling in the introduction to show the landscape and effects of rainfall changes.

MINOR ISSUES:

There is still inconsistent capitalization between “county” and “County” to refer to the study region.

Format the tables consistently. Early tables have borders, later tables (Tables 4-6) do not.

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

Do you want your identity to be public for this peer review? If you choose “no”, your identity will remain anonymous but your review may still be made public.

For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: Yes: Hiep Duc Nguyen

Reviewer #3: No

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[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

Climate change scenario projections and their implications on food systems in Taita Taveta County, Kenya

PCLM-D-22-00098R2

Dear Dr. Nyambariga,

We are pleased to inform you that your manuscript 'Climate change scenario projections and their implications on food systems in Taita Taveta County, Kenya' has been provisionally accepted for publication in PLOS Climate.

Before your manuscript can be formally accepted you will need to complete some formatting changes, which you will receive in a follow-up email from a member of our team. 

Please note that your manuscript will not be scheduled for publication until you have made the required changes, so a swift response is appreciated.

IMPORTANT: The editorial review process is now complete. PLOS will only permit corrections to spelling, formatting or significant scientific errors from this point onwards. Requests for major changes, or any which affect the scientific understanding of your work, will cause delays to the publication date of your manuscript.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they'll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact climate@plos.org.

Thank you again for supporting Open Access publishing; we are looking forward to publishing your work in PLOS Climate.

Best regards,

Noureddine Benkeblia, Dr. Sci., Dr. Agr.

Academic Editor

PLOS Climate

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After careful consideration of the revised manuscript, it is noted that the reviewers' comments have been rigorously addressed. Therefore, the manuscript might be accepted for publication under its present form.

Reviewer Comments (if any, and for reference):