{"type":"script","doc_desc":{"producers":[{"name":"Reproducibility WBG","abbr":"DIME","affiliation":"World Bank - Development Impact Department","role":"Verification and preparation of metadata"}],"prod_date":"2025-02-06","version":"1"},"project_desc":{"authoring_entity":[{"name":"Rafael Van der Borght","email":"rvanderborght@worldbank.org","affiliation":"World Bank"},{"name":"Oscar A. Ishizawa","email":"oishizawa@worldbank.org","affiliation":"World Bank"},{"name":"Jean Thuret","email":"jeanthuret34@gmail.com"},{"name":"Joaquin Mu\u00f1oz","email":"jmunozdiaz@worldbank.org","affiliation":"World Bank"}],"output":[{"title":"Dry Spells, Urban Swells: Analyzing the Drought-Induced Expansion of Cities in Sub-Saharan Africa","type":"Working Paper","description":"Policy Research Working Paper (PRWP)"}],"datasets":[{"name":"Standardized Precipitation-Evapotranspiration Index (SPEI) data","note":"Source: Beguer\u00eda, Santiago; Vicente Serrano, Sergio M.; Reig-Gracia, Fergus; Latorre Garc\u00e9s, Borja; 2023; SPEIbase v.2.8\nFilename: data\/SPEI\/spei12month_1901_2021.nc","uri":"https:\/\/doi.org\/10.20350\/digitalCSIC\/15121","access_type":"Publicly available and included in the reproducibility package."},{"note":"Source: Africapolis\nLocated at: data\/Africapolis_2020\/africapolis2020.gpkg","uri":"https:\/\/africapolis.org\/en\/data","name":"Housing and population censuses data","access_type":"Publicly available and included in the reproducibility package."},{"name":"World Settlement Footprint data","note":"Source: Development Data Hub\nLocated at: data\/WSF_EVO","uri":"https:\/\/datacatalog.worldbank.org\/search\/dataset\/0060310\/satellite%20monitoring%20service%20of%20urbanization%20in%20africa%20%28world%20settlement%20footprint%29?version=2","access_type":"Publicly available and included in the reproducibility package."},{"uri":"https:\/\/human-settlement.emergency.copernicus.eu\/download.php","name":"Global Human Settlement (GHS) Population Grid data","note":"Source: Human Settlement Emergency Copernicus\nLocated at: data\\GHS_POP","access_type":"Publicly available and included in the reproducibility package."},{"name":"Global Human Settlement (GHS) Model Grid data","note":"Source: Human Settlement Emergency Copernicus\nLocated at: data\\GHS_SMOD","access_type":"Publicly available and included in the reproducibility package.","uri":"https:\/\/human-settlement.emergency.copernicus.eu\/download.php?ds=smod"},{"name":"Global Human Settlement (GHS) built-up surface data","note":"Source: Human Settlement Emergency Copernicus\nLocated at: \\data\\GHS_BUILT_S","access_type":"Publicly available and included in the reproducibility package."},{"name":"Agriculture value added data","note":"Source: World Development Indicators\nLocated at: \/data\/WDI_agriculture_share_gdp\/WDI_agriculture_share_gdp.xlsx","access_type":"Publicly available and included in the reproducibility package.","uri":"https:\/\/databank.worldbank.org\/source\/world-development-indicators"},{"name":"GDP per Capita data","note":"Source: World Development Indicators\nLocated at: \/data\/WDI_GDP_per_capita\/","access_type":"Publicly available and included in the reproducibility package.","uri":"https:\/\/databank.worldbank.org\/source\/world-development-indicators"},{"uri":"https:\/\/crudata.uea.ac.uk\/cru\/data\/hrg\/cru_ts_4.08\/","name":"Rainfall data","note":"Source: University of East Anglia Climatic Research Unit (CRU) \nLocated at: \/data\/CRU_rainfall\/cru-x0.5_timeseries_pr_timeseries_annual_1901-2022_mean_historical_cru_ts4.07_mean.xlsx","access_type":"Publicly available and included in the reproducibility package."}],"title_statement":{"title":"Reproducibility package for  Dry Spells, Urban Swells: Analyzing the Drought-Induced Expansion of Cities in Sub-Saharan Africa","idno":"RR_SSA_2025_270"},"acknowledgment_statement":"We thank Megha Mukim for useful comments on a previous version of this manuscript as well as Romain Fourmy and Jin Rui Yap for their support processing some of the data used in this study. This work has been financed by the Sub-Saharan Africa Disaster Risk Analytics Program which is funded through the Global Facility for Disaster Reduction and Recovery (GFDRR). This paper is a product of the Urban, Disaster Risk Management, Resilience Land GP. It is part of a larger effort by the World Bank to provide open access to its research and make a contribution to development policy discussions around the world. Policy Research Working Papers are also posted on the Web at http:\/\/www.worldbank.org\/prwp. The author(s) may be contacted at rvanderborght@worldbank.org, oishizawa@worldbank.org.","production_date":"2025-02","abstract":"Droughts are increasingly cited as a driver of urbanization across Sub-Saharan Africa, yet little is known about the role they play in shaping the spatial expansion of cities. Combining satellite imagery on built-up areas with climatic data for the period 1984-2015, this study empirically examines whether and to what extent droughts influences the spatial expansion of African cities. It further investigates the heterogeneity of these effects across cities and countries. Findings indicate that extreme droughts significantly accelerate the built-up growth rate of cities, while more frequent but less severe droughts have negligible impacts. Importantly, these effects are strongly differentiated across cities. The 1% most extreme droughts boost by 75% the average speed at which new settlements emerge in the surroundings of a country's largest city, yet they do not alter the expansion of other smaller cities and towns. These drought-induced effects intensify the sprawl of the largest cities and bear important policy implications: extreme droughts put additional pressure on the largest and often overcrowded cities, potentially deepening congestion effects; they also contribute to exacerbate the speed at which cities expand in flood prone areas, thereby magnifying urban flood risk. As climate changes, the frequency of both extreme droughts and extreme rainfall events is projected to increase across the region, aggravating the likelihood of future drought-induced expansions of the largest cities and worsening urban flood risk prospects. These findings call for urgent and tailored risk reduction measures in both cities and rural areas.","geographic_units":[{"name":"Sub-Saharan Africa","code":"SSA","type":"Region"}],"keywords":[{"name":"Drought"},{"name":"City extent"},{"name":"Climate risk"},{"name":"Earth Observations"},{"name":"Africa"}],"language":[{"name":"English","code":"EN"}],"software":[{"name":"R","version":"4.4.0","library":[""]},{"name":"Python","version":"3.11"}],"scripts":[{"file_name":"RR_SSA_2025_270","zip_package":"RR_SSA_2025_270.zip","title":"Reproducibility package (data and code) for Dry Spells, Urban Swells: Analyzing the Drought-Induced Expansion of Cities in Sub-Saharan Africa","dependencies":"All dependencies are included in \"renv.lock\" for the R code and \"environment.yml\" for the Python code."}],"data_statement":"All data sources are publicly available and included in the reproducibility package.","reproduction_instructions":"To successfully reproduce the analysis, follow these steps:\n1. Install the provided Python environment called `environment.yml` file\n2. Open the Jupyter Notebook `1. dataset_creation.ipynb` located in the root directory. Update the directory path in cell 2.\n3. Run `2. Regressions.R` after updating the directory.\n4. After completing the above steps, run the following files to generate figures and tables:\n`3. figures_1_3_5_6_7.R`\n `4. figures_2_4.ipynb`\n `5. Main plots.R`\n","technology_environment":"Paper exhibits were reproduced on a computer with the following specifications:\n\u2022 OS: Windows 10 Enterprise, version 22H2\n\u2022 Processor: Intel(R) Xeon(R) Gold 6132 CPU @ 2.60GHz 2.60 GHz (2 processors)\n\u2022 Memory available: 128 GB\n\u2022 Software version: Python 3.11, R 4.3.2","technology_requirements":"~ 3 hours","repository_uri":[{"name":"Reproducible Research Repository (World Bank)","uri":"https:\/\/reproducibility.worldbank.org"}],"disclaimer":"The materials in the reproducibility packages are distributed as they were prepared by the staff of the International Bank for Reconstruction and Development\/The World Bank. The findings, interpretations, and conclusions expressed in this event do not necessarily reflect the views of the World Bank, the Executive Directors of the World Bank, or the governments they represent. The World Bank does not guarantee the accuracy of the materials included in the reproducibility package.","license":[{"name":"Modified BSD3","uri":"https:\/\/opensource.org\/license\/bsd-3-clause\/"}],"contacts":[{"name":"Joaquin Munoz Diaz","affiliation":"World Bank","email":"jmunozdiaz@worldbank.org"},{"name":"Reproducibility WBG","affiliation":"World Bank","email":"reproducibility@worldbank.org"}],"topics":[{"id":"Q54","vocabulary":"JEL Classifications","uri":"https:\/\/www.aeaweb.org\/econlit\/jelCodes.php?view=jel","parent_id":"Q5","name":"Climate \u2022 Natural Disasters and Their Management \u2022 Global Warming"},{"id":"O18","vocabulary":"JEL Classifications","uri":"https:\/\/www.aeaweb.org\/econlit\/jelCodes.php?view=jel","parent_id":"O1","name":"Urban, Rural, Regional, and Transportation Analysis \u2022 Housing \u2022 Infrastructure"},{"id":"O13","vocabulary":"JEL Classifications","uri":"https:\/\/www.aeaweb.org\/econlit\/jelCodes.php?view=jel","parent_id":"O1","name":"Agriculture \u2022 Natural Resources \u2022 Energy \u2022 Environment \u2022 Other Primary Products"},{"id":"R11","vocabulary":"JEL Classifications","uri":"https:\/\/www.aeaweb.org\/econlit\/jelCodes.php?view=jel","parent_id":"R1","name":"Regional Economic Activity: Growth, Development, Environmental Issues, and Changes"}]},"tags":[{"tag":"DOI"},{"tag":"Open code"},{"tag":"Open data"}],"schematype":"script"}