Unpacking the role of climate variability on displacement in the Greater Horn of Africa

Victor Villa; Pierfrancesco Rolla; Marina Mastrorillo; Anna Belli; Grazia Pacillo; Peter Läderach

doi:10.1371/journal.pclm.0000594

Peer Review History

Original SubmissionFebruary 14, 2025
17 Apr 2025 Decision Letter - Jason Morgan, Editor PCLM-D-25-00031 Unpacking the role of climate variability on displacement in the Greater Horn of Africa PLOS Climate Dear Dr. Villa, 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. Your manuscript has been assessed by two reviewers. While both reviewers highlight the importance of the area of study, they have raised significant concerns regarding the methodological approach, conceptual definitions and overall validity within your work, which prevents publication of your current manuscript. We recommend that you consider these comments carefully in preparing a revised manuscript and rebuttal response to the reviewers. Please note that failure to adequately address all reviewer comments may result in rejection of your work. Please submit your revised manuscript by Jun 01 2025 11:59PM. 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, Jason Morgan Staff Editor PLOS Climate Comments from PLOS Editorial Office: We note that a reviewer has made a suggestion that you cite specific previously published work. As always, we recommend that you please review and evaluate the requested works to determine whether they are relevant and should be cited. It is not a requirement to cite these works and you may remove any added citations before the manuscript proceeds to publication. We appreciate your attention to this request. Journal Requirements: 1. Please note that PLOS Climate has specific guidelines on code sharing for submissions in which author-generated code underpins the findings in the manuscript. 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(http://www.usgs.gov) * PlaniGlobe - All maps are published under a Creative Commons license so please cite “PlaniGlobe, http://www.planiglobe.com, CC BY 2.0” in the image credit after the caption. (http://www.planiglobe.com/?lang=enl) * Natural Earth - All maps are public domain. (http://www.naturalearthdata.com/about/terms-of-use/) Additional Editor Comments (if provided): [Note: HTML markup is below. Please do not edit.] 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: Partly Reviewer #2: No ******** 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: I don't know Reviewer #2: No ****** 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: No ****** 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 ****** 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: Dear authors Thank you for the well-written manuscript. There is valuable data and discussion, and the manuscript has the potential to provide valuable contributionsten. However it has some substantive challenges that should be addressed before it is published. The main issue is the claims you make and conclusions you draw on the basis of the data you have. This can be addressed by more nuanced and limited claims and conclusions that be supported by the data and make room for its limitations. There are challenges regarding how displacement is defined and the conflation of different types of movement that are a main weakness at the moment and need to be addressed. There needs to be much more rigor in the use of different concepts and categories. I have also included comments on structure and methods and some detailed comments to smaller issues throughout the paper. See the attached document for the full review. Once you've addressed these comments you will have a much stronger paper with an excellent contribution to the literature. All the best Reviewer #2: PCLM-D-25-00031 Unpacking the role of climate variability on displacement in the Greater Horn of Africa This manuscript investigates the relationship between climate variability and self-reported displacement in the Greater Horn of Africa, utilizing data from over 54,000 individuals recorded at Flow Monitoring Points (FMPs) through the IOM’s Displacement Tracking Matrix. It adopts a subjective, actor-centered lens by focusing on perceived rather than formally defined displacement and classifies climatic conditions using the Palmer Drought Severity Index for the three months preceding departure. The findings, based on linear probability models, suggest that wet and extremely wet conditions increase the likelihood of displacement, while dry conditions have no significant effect, and extremely dry conditions are negatively associated with perceived displacement. The authors attribute these patterns to two mechanisms: livelihood disruption in agricultural areas, especially due to flooding, and a climate–conflict interaction in which wetter conditions increase the risk of violence, thereby contributing to displacement. While the topic is timely and policy-relevant, I am unable to recommend the manuscript for publication in PLOS Climate due to substantial theoretical and methodological shortcomings that limit its originality, analytical depth, and causal credibility. Specific comments: Although the emphasis on self-perceived displacement offers a more nuanced, subjective perspective on climate mobility, the manuscript’s contribution is limited in terms of novelty. Numerous studies have already examined individual-level mobility responses to climate variability using survey data, many of which are cited in the manuscript. Furthermore, a recent PLOS ONE study (https://doi.org/10.1371/journal.pone.0297079, which is not referenced) reports similar findings: individuals affected by sudden-onset events such as floods were more likely to identify as environmental migrants, whereas those experiencing slow-onset processes like droughts tended to self-identify as voluntary or economic migrants. The parallels between this study and the manuscript under review diminish the distinctiveness of its empirical contribution. The manuscript attempts to differentiate between slow- and rapid-onset climatic events and between voluntary and forced migration. However, it lacks meaningful engagement with established theoretical frameworks that could enhance its conceptual foundations, particularly aspiration-capability models or threshold theories of migration. These frameworks do more than offer variables to control for, in that, they provide structured insights into how environmental stressors intersect with individual agency, resource availability, institutional constraints, and the timing of migration decisions. Equally concerning is the under-theorization of the manuscript’s central concept: "perceived displacement." The authors fail to explore how such self-identifications are shaped by social context, framing effects during interviews, or post-hoc rationalizations. A deeper engagement with these issues would add much-needed theoretical sophistication and interpretive clarity. Methodologically, the reliance on linear probability models (LPMs) is problematic. Although LPMs are commonly used for binary outcomes due to their simplicity, they suffer from known limitations, most notably, the possibility of generating predicted probabilities outside the [0,1] range. This issue is exacerbated in interaction models, where the relationship between variables is unlikely to be linear. More appropriate alternatives, such as logistic or probit models, would offer greater statistical validity while maintaining interpretability. Compounding this concern is the absence of any strategy to address endogeneity. The analysis does not employ instrumental variable techniques or alternative identification strategies to deal with potential issues such as selective exposure to climate risks, measurement error in the geographic data, or reverse causality. These omissions undermine the causal claims made throughout the paper. Additionally, although the authors acknowledge that the sample includes only individuals who have already migrated, raising the possibility of selection bias, they do not take any steps to mitigate this limitation. Robustness checks, such as bounding exercises or comparisons with non-migrant populations, would help gauge how sensitive the results are to this bias. The lack of such strategies further weakens the manuscript’s ability to support generalizable or causal conclusions. The modeling of conflict as a contemporaneous variable, occurring within three months of reported displacement, raises further concerns. The authors do not address the possibility of reverse causality, where displacement may contribute to local conflict dynamics. Nor do they explore the role of potentially confounding factors such as political instability or local governance breakdowns, which could simultaneously drive both conflict and migration. Without establishing a clearer temporal sequence or employing methods to address these endogeneity risks, the proposed climate–conflict–displacement pathway remains speculative. The use of land cover data to identify cropland areas as a proxy for agricultural livelihoods is creative but ultimately insufficient. The manuscript provides no validation or ground-truthing to confirm whether the migrants indeed came from farming households. Without direct data on household occupation or income sources, the claim that flooding disrupts agricultural livelihoods and thereby triggers displacement remains largely inferential. Incorporating such household-level information would have significantly strengthened the causal link between environmental shocks and migration behavior. Finally, the data collection strategy poses important limitations for external validity. The study is based exclusively on individuals intercepted at FMPs, that is, non-random, strategically located monitoring points, typically situated near borders or transit corridors. This approach inherently excludes migrants using informal or less-monitored routes and may therefore misrepresent broader patterns of displacement. While the authors briefly acknowledge this limitation, they do not sufficiently discuss how it affects the generalizability of their findings or consider how sampling bias might skew the demographic and socioeconomic profile of the observed population. A more explicit treatment of these issues would enhance the study’s methodological transparency and help readers better interpret its implications. ****** 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: No Reviewer #2: No ******** [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. Attachments Attachment Submitted filename: Horn of Africa displacement perception review.docx Attachment Submitted filename: Review PCLM-D-25-00031.pdf https://doi.org/10.1371/journal.pclm.0000594.r001
Revision 1
29 Jul 2025 Author Response We would like to sincerely thank the editor and both reviewers for their constructive and thoughtful feedback on our manuscript, “Unpacking the role of climate variability on displacement in the Greater Horn of Africa.” We found the comments to be highly valuable, and we have carefully revised the manuscript in response to each point raised. Below we provide a brief summary of the key improvements made to address the reviewers’ concerns. Response to Reviewer 1 Reviewer 1 raised important conceptual and definitional concerns around the use of displacement categories, self-reported variables, and the conflation of mobility types. We have addressed these in the following ways: Terminological precision: We replaced all references to “perception” or “feeling” of displacement with the more accurate term “self-reported displacement.” This is now consistently used throughout the manuscript. Conceptual clarity: We added a new section early in the manuscript (Section 2) that discusses key definitions of displacement, migration, and forced mobility, and engages directly with relevant literature on the distinctions among these categories. Improved framing of findings: We revised our interpretations and conclusions to avoid overreaching claims. We now explicitly acknowledge the limitations of our data (particularly the binary nature of the displacement variable and the context of data collection at Flow Monitoring Points), and we present our findings as associations rather than causal effects. Expanded discussion on bias: We strengthened the discussion around potential social desirability and context-induced reporting biases (especially for individuals interviewed at border points) and clarified their implications for our findings. Revised structure: We reduced the length of the introduction and moved conceptual discussions into a dedicated section as suggested. We also improved language precision in several parts of the manuscript (e.g., avoiding conflations between “migrants” and “displaced,” or between “exposure” and “vulnerability”). Response to Reviewer 2 Reviewer 2 provided in-depth feedback on the theoretical framing, methodological rigor, and robustness of the empirical analysis. We have substantially revised the manuscript to address these critiques: Theoretical enhancement: We developed a new theoretical framework section grounded on exisisting migration frameworks that provides stronger grounding for our interpretation of the results. Modeling clarifications and robustness checks: We retained linear probability models for ease of interpretation but better explain why we belieive that this is not creating any issue in the estimation (based on existing literature) and that our robustness section partially addresses concerns by including: Logistic regression specifications, Propensity score matching (PSM), Inverse probability weighting (IPW), Coefficient stability test, and Fixed effects for interview location and region-year interactions. Clarified empirical scope: We emphasize that our analysis is exploratory and descriptive, not causal. We revised the text to reflect this more consistently across all sections. Data and sampling transparency: We now provide a clearer explanation of our sampling limitations due to the use of Flow Monitoring Points, and we discuss their implications for external validity and representativeness. Geospatial and livelihood assumptions: We clarified our geocoding methodology and addressed limitations in using land cover proxies for agricultural livelihoods. While we lack direct occupation data, we support our assumptions with contextual evidence from the region. Conflict pathway interpretation: We explicitly state the limitations of our mediation analysis involving conflict, noting that it is speculative and subject to potential endogeneity and omitted variable bias. We believe that these changes have significantly strengthened the manuscript’s conceptual foundations, methodological transparency, and empirical interpretation. We are grateful for the reviewers’ and editor’s insights, which have greatly improved the clarity and scholarly contribution of our work. Attachments Attachment Submitted filename: Response to Reviewers.pdf https://doi.org/10.1371/journal.pclm.0000594.r002
8 Oct 2025 Decision Letter - Jason Morgan, Editor PCLM-D-25-00031R1 Unpacking the role of climate variability on displacement in the Greater Horn of Africa PLOS Climate Dear Dr. Villa, 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. Your manuscript has been assessed by one further reviewer. While they indicate interest in your work, they raise several points for your attention. Please consider these points carefully when preparing your revised manuscript and point-by-point response document. Please submit your revised manuscript by Nov 22 2025 11:59PM. 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, Jason Morgan Staff Editor PLOS Climate Journal Requirements: If the reviewer comments include a recommendation to cite specific previously published works, please review and evaluate these publications to determine whether they are relevant and should be cited. There is no requirement to cite these works unless the editor has indicated otherwise. Additional Editor Comments (if provided): [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 #3: (No Response) ******** 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 #3: Yes ****** 3. Has the statistical analysis been performed appropriately and rigorously? Reviewer #3: Yes ****** 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 #3: No ****** 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 #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 #3: The paper “Unpacking the role of climate variability on displacement in the Greater Horn of Africa” is a strong analysis that is clearly explained and with limitations that are thoroughly addressed. It is well situated in the literature and is thus positioned to make a substantial contribution to our understanding of mobility, migration, displacement, and the intertwined effects of climate and conflict in driving displacement as a distinct form of mobility. I give just a few minor comments below, with the intention of making minor improvements to an already strong paper. It appears the authors still need to address the data sharing requirement. “Guided by well-established conceptual frameworks from the climate-mobility literature” – say more about which ones, and provide citations here, to assist your readers who are interested in this literature. Is your study also unique more broadly, or are similar methods used in other regions? Relatedly, where are these FMP data available for/are they available for other regions? If so, how did you choose your study area? Say a bit more about the 120,000 observations you excluded and how you decided to focus on and define the region of interest, as the respondents don’t seem to all be from the geographic region on which you’re focusing. In figure 2, is it possible to explain further what the figures show and what you mean by they “do not overlap” ? This is unclear to me. Perhaps rather than “overlap”, simply say they are statistically different? In the regression analysis, you could make it explicit that you use the LPM because you have a binary dependent variable. Are there other considerations why the LPM also makes sense here, as opposed to say a logistic model? If so, add mention of those too, to help explain why you use the LPM. – disregard this comment, you explain further below! Good. And you discuss even further in section 5, also good. Wetter conditions driving displacement? Interesting discussion of your findings here, building on the literature, especially slow onset vs. immediate forced displacement. Could you envision a context (perhaps at a different time in this location, or in another location) where drought could be more severe and act more like the extreme wet conditions in this analysis in terms of displacement? You say, “Instead, there is considerable scope for a more rigorous regression analysis.” But are these data available? Do you intend to perform such an analysis? Does the dismantling of USAID impact data collection and/or the policy recommendations you suggest? If so, would be good to mention as real-world context, for both (data collection and policy recommendations). If not, disregard. What do the climate projections suggest is likely for this region moving forward? (More drought? Or more extreme wet?) Typos I noticed while reading to search for and correct: “lung-run” “wwe” “that areas” “youth is” “into three” ****** 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 #3: No ******** [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". 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Revision 2
1 Dec 2025 Author Response Q.1 - It appears the authors still need to address the data sharing requirement. A.1 – We thank the reviewer for raising this important point. However, the data used in this study belongs to the International Organization for Migration (IOM) and was accessed by the authors under a formal data-sharing agreement that restricts public dissemination. We have officially requested IOM’s authorization to make the dataset publicly available. Unfortunately, the IOM Legal Office did not grant consent for data sharing, citing confidentiality and data protection considerations. We have received an official letter from IOM’s Legal Office confirming this restriction, which was already shared with the journal in the first round of review. Q.2 - “Guided by well-established conceptual frameworks from the climate-mobility literature” – say more about which ones, and provide citations here, to assist your readers who are interested in this literature. A.2 – We appreciate the reviewer for raising this valuable comment. We have clarified in the introduction which conceptual frameworks from the climate-mobility literature guide our analysis, to help orient readers interested in this literature. Specifically, we now indicate in the introduction that our study builds on three key frameworks detailed in Section 2: (1) the migration threshold theories (Bardsley & Hugo, 2010; McLeman, 2018), (2) the environmentally induced migration typology (Renaud et al., 2011), and (3) the aspiration-capability framework (De Haas, 2021; Carling & Schewel, 2020). Q.3 - Is your study also unique more broadly, or are similar methods used in other regions? A.3 – We thank the reviewer for raising this question regarding the uniqueness of our study. In the introduction, we clarify that our main contribution lies in its regional and empirical focus rather than in the use of entirely new statistical methods. While similar quantitative approaches have been applied elsewhere (e.g., Mueller et al., 2014 in Pakistan; Cattaneo & Peri, 2016 in Sub-Saharan Africa; Bertoli et al., 2022 in West Africa), our work is the first to apply this framework to the Greater Horn of Africa using such a large, multi-country dataset. Furthermore, the study leverages the IOM Flow Monitoring Survey (FMS) to analyze both internal and cross-border mobility from an individual perspective, focusing specifically on self-reported displacement rather than broader migration flows. This conceptual and empirical angle, examining how individuals themselves report being displaced under varying climate conditions, remains largely unexplored in any regional context. In addition, we introduce methodological innovation through a semi-automated geocoding routine in R, which extracts precise GPS coordinates from respondents’ reported villages of departure using the Google Maps API. This approach allows us to link individual-level mobility information to high-resolution climatic, environmental, and conflict data, thereby reducing spatial misclassification and improving analytical precision. To our knowledge, this is the first time such a method has been applied to the IOM FMS dataset or to displacement studies more broadly. We believe that these elements, taken together, make this study a unique contribution to the climate-mobility literature. We added the following sentence at the end of the introduction to further highlight the contributions and the uniqueness of this study “This study makes a unique contribution to the climate-mobility literature by exploiting a large multi-country dataset on mobile populations in the Greater Horn of Africa and an advanced spatial matching procedure that links individual mobility histories to high-resolution climatic indicators. Together, these features allow for a detailed examination of self-reported displacement, of differences between internal and cross-border movements, and of the mechanisms through which climate variability shapes displacement outcomes.”. Q.4 - Relatedly, where are these FMP data available for/are they available for other regions? If so, how did you choose your study area? A.4 - We thank the reviewer for this pertinent question. The IOM Flow Monitoring Points (FMPs) are part of the global Displacement Tracking Matrix (DTM) system and are currently established in several countries across the Globe. These points monitor mobility along key migration routes, including the Central and Western Mediterranean, the Sahel, West and Central Africa, and the East and Horn of Africa (EHoA). For this study, we focus on the Greater Horn of Africa because it is among the regions most affected by climate-related displacement and overlapping conflict risks, this is extensively discussed in the introduction. EHoA is also the only subregion where the FMS data provide sufficiently rich and consistent temporal and spatial coverage over 2018–2022. In addition, the research team is based in Nairobi and collaborates closely with the IOM Regional Office for East and Horn of Africa, which facilitated data access through a formal data-sharing agreement. For these reasons (data availability and consistency, the relevance of the issue in the region, and institutional collaboration between organizations we selected the Greater Horn of Africa as the focus of our analysis. Apart from these practical motivations, we have also strengthened the reason for choosing this region in the data section to give substantial attention to the regional context of the Greater Horn of Africa (climate shocks and displacement) as follows “Although FMSs are implemented in many countries worldwide as part of IOM’s global DTM system, in this study we focus on the network of FMPs located within the Greater Horn of Africa. We selected this region because it is one of the areas most affected by recurrent climate shocks and climate-related displacement and because the FMS provides the most complete and temporally consistent coverage there over the period 2018-2022.” This provides readers with a clearer rationale for why this specific region was chosen and how it fits the objectives of the study. Q.5 - Say a bit more about the 120,000 observations you excluded and how you decided to focus on and define the region of interest, as the respondents don’t seem to all be from the geographic region on which you’re focusing. A.5 – We thank the reviewer for raising this pertinent point that, together with the previous comment, has helped us to strengthen the rational of choosing our geographical focus. We have clarified in the Data section that although Flow Monitoring Points are implemented in many countries worldwide as part of IOM’s global DTM system, in this study we focus on the network of FMPs located within the Greater Horn of Africa due to the relevance of these issues. In the same sentence, we specified that all respondents in our dataset were interviewed at FMPs within this region. However, these FMPs captured also individuals that originate from or travel to locations lying just beyond some definitions of the Greater Horn of Africa but were already moving through this regional system at the time of interview. Regarding the reduction from the original sample to the final analytical sample, we have clarified that the approximately 120,000 excluded observations are dropped because of missing or incomplete information on key variables required for the analysis. In particular, we exclude individuals who did not report a place of departure, a departure date, their self-reported displacement status, or core socio-demographic characteristics (such as age, gender, education, or employment). After applying these completeness criteria, our final dataset comprises 54,131 individuals interviewed in 85 FMPs between 2018 and 2022. We have revised the relevant paragraph in the Data section to reflect this more clearly and to avoid any ambiguity around the definition of the region of interest and the reasons for excluding observations. Q.6 - In figure 2, is it possible to explain further what the figures show and what you mean by they “do not overlap” ? This is unclear to me. Perhaps rather than “overlap”, simply say they are statistically different? A.6 – We thank the reviewer for this helpful comment. We agree that the expression “do not overlap” was unclear and potentially misleading. Our aim with Figure 2 is to provide visual descriptive evidence on whether displaced and non-displaced individuals experienced different climatic conditions prior to departure and to show that the distributions of the climatic indicators differ between the two groups. We have therefore revised the text below Figure 2. The wording “do not overlap” has been removed and substituted with a clearer explanation on the visual and statical difference of the distributions between displaced and not displaced. We improved the sentence as follows: “Visually, the curves for displaced individuals are shifted towards wetter-than-usual conditions for precipitation, PDSI and SPEI, and towards slightly cooler values for the temperature anomaly, relative to the curves for non-displaced individuals. These patterns suggest that, in the three months before departure, displaced people may have been exposed to wetter climatic conditions (higher precipitation, PDSI and SPEI) and lower temperatures compared with non-displaced individuals. A Kolmogorov–Smirnov (K–S) test, reported in each panel of Figure 2, formally confirms these differences by rejecting the null hypothesis that the distributions for displaced and non-displaced individuals are identical for all four indicators (p < 0.001).” Q.7 - In the regression analysis, you could make it explicit that you use the LPM because you have a binary dependent variable. Are there other considerations why the LPM also makes sense here, as opposed to say a logistic model? If so, add mention of those too, to help explain why you use the LPM. – disregard this comment, you explain further below! Good. And you discuss even further in section 5, also good. A.7 – We thank the reviewer for this comment and for subsequently noting that the point is already addressed in the manuscript. As indicated, we explicitly justify the use of the linear probability model (LPM) for our binary dependent variable in the methodology section and further discuss this choice, including its advantages and limitations relative to non-linear models such as logit, in Section 5. In light of the reviewer’s follow-up note, we have not introduced additional changes to this part of the analysis. Q.8 - Wetter conditions driving displacement? Interesting discussion of your findings here, building on the literature, especially slow onset vs. immediate forced displacement. Could you envision a context (perhaps at a different time in this location, or in another location) where drought could be more severe and act more like the extreme wet conditions in this analysis in terms of displacement? A.8 – We thank the reviewer for this insightful question. Our empirical results refer to a recent period in which rapid-onset wet shocks and flood-related hazards appear to be the main climatic triggers of self-reported displacement in the Greater Horn of Africa. In revising the manuscript, we consulted recent regional climate-model literature for East Africa, including a 2024 review that we now cite in the conclusion. This work indicates a robust increase in temperatures and a tendency towards more frequent and prolonged hydrologic extremes and rapid switches between severe droughts and flood events. Building on this evidence, and in connection with our response to Comment 11, we have added two sentences in the conclusion explaining that, in a warmer future characterized by more intense and possibly faster-onset droughts alongside flood hazards, severe drought episodes could plausibly act as more acute triggers of displacement, more closely resembling the role of extreme wet conditions documented in our analysis. Q.9 - You say, “Instead, there is considerable scope for a more rigorous regression analysis.” But are these data available? Do you intend to perform such an analysis? A.9 - We thank the reviewer for raising this point. We agree that the original sentence was confusing, as such data are, to the best of our knowledge, not currently available. To avoid any misunderstanding, we have removed the sentence suggesting “considerable scope for a more rigorous regression analysis” with the current data. In the revised conclusion, after outlining the limitations of the FMS/FMP dataset (cross-sectional design, lack of representativeness, and potential selection, measurement and social desirability biases), we now clarify that our findings should be interpreted as associations and explicitly state that more rigorous causal analyses would require purpose-designed longitudinal or experimental data. We also add that analyses such as ours can help inform the design of future mobility and displacement data collection (e.g. sampling strategies, longitudinal follow-up, systematic climate modules), thereby creating the conditions for more robust regression analyses in subsequent research. Q.10 - Does the dismantling of USAID impact data collection and/or the policy recommendations you suggest? If so, would be good to mention as real-world context, for both (data collection and policy recommendations). If not, disregard. A.10 - We thank the reviewer for this pertinent question. The FMS data used in this paper were collected by IOM with support from multiple donors, and we do not have sufficiently detailed information to attribute the specific waves we analyse to USAID funding. However, we agree that the dismantling of USAID is likely to affect both future data collection and the types of policies we discuss. To reflect this real-world context, we have added a sentence in the concluding policy discussion noting that these funding and policy needs arise at a time when major bilateral development programmes, including USAID, are being dismantled or significantly reduced, which may narrow the fiscal space for climate adaptation, livelihood assistance and social protection, and that this underscores the importance of safeguarding and diversifying funding for displacement monitoring and climate-adaptive interventions. Q.11 - What do the climate projections suggest is likely for this region moving forward? (More drought? Or more extreme wet?) A.11- We thank the reviewer for this important point. To address it, we consulted recent regional climate-projection studies for East Africa, including a 2024 synthesis that we now reference in the conclusion. These assessments indicate a robust, scenario-independent increase in temperatures throughout the twenty-first century, together with a tendency towards more frequent and prolonged hydrologic extremes and rapid alternations between severe droughts and flood events, while projections of mean rainfall remain highly uncertain. We have added two sentences in the conclusion summarising these projections and explaining that they imply increasing risks from both flood- and drought-related displacement. We also explicitly link this to our discussion of mechanisms, noting that more severe future droughts could alter the balance we currently observe between slow-onset and rapid-onset climate shocks. Q.12 - Typos I noticed while reading to search for and correct: “lung-run” “wwe” “that areas” “youth is” “into three” A.12 – We thank the reviewer for spotting these typos. We have carefully revised the manuscript and corrected all the flagged instances. Attachments Attachment Submitted filename: Response to the Reviewer 2nd round.pdf https://doi.org/10.1371/journal.pclm.0000594.r004
16 Dec 2025 Decision Letter - Shah Md Atiqul Haq, Editor <p>Unpacking the role of climate variability on displacement in the Greater Horn of Africa PCLM-D-25-00031R2 Dear Villa, We are pleased to inform you that your manuscript 'Unpacking the role of climate variability on displacement in the Greater Horn of Africa' 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, Shah Md Atiqul Haq Academic Editor PLOS Climate ********************************************************* Additional Editor Comments (if provided): Reviewer Comments (if any, and for reference): Reviewer's Responses to Questions Comments to the Author 1. 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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 #3: Yes ****** 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 #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 #3: The authors of the paper “Unpacking the role of climate variability on displacement in the Greater Horn of Africa” have thoroughly responded to all of my concerns. Furthermore, the authors have adequately addressed the data sharing requirement, which I believe should not prohibit publication of this paper. I believe the paper is ready for publication and makes a valuable contribution. ****** 7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). 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