Modelling the potential impacts of afforestation on extreme precipitation over West Africa

  • Romaric C. Odoulami
  • Babatunde J. Abiodun
  • Ayodele E. Ajayi


This study examines how afforestation in West Africa could influence extreme precipitation over the region, with a focus on widespread extreme rainfall events (WEREs) over the afforestation area. Two regional climate models (RegCM and WRF) were applied to simulate the present-day climate (1971–2000) and future climate (2031–2060, under IPCC RCP 4.5 emission scenario) with and without afforestation of the Savannah zone in West Africa. The models give a realistic simulation of precipitation indices and WEREs over the subcontinent. On average, the regional models projected future decreases in total annual wet day precipitation (PRCPTOT) and total annual daily precipitation greater than or equal to the 95th percentile of daily precipitation threshold (R95pTOT) and increases in maximum number of consecutive dry days (CDD) over Sahel. Over Savannah, the models projected decreases in PRCPTOT but increases in R95pTOT and CDD. Also, an increase in WEREs frequency is projected over west, central and east Savannah, except that RegCM simulated a decrease in WEREs over east Savannah. In general, afforestation increases PRCPTOT and R95pTOT but decreases CDD over the afforestation area. The forest-induced increases in PRCPTOT and decreases in CDD affect all ecological zones in West Africa. However, the simulations show that afforestation of Savannah also decreases R95pTOT over the Guinea Coast. It further increases WEREs over west and central Savannah and decreases them over east Savannah because of the local decrease in R95pTOT. Results of this study suggest that the future changes in characteristics of extreme precipitation events over West Africa are sensitive to the ongoing land modification.


Regional climate model Climate change Afforestation Extreme precipitation Climate extremes West Africa 



The first author was supported by the German Federal Ministry of Education and Research (BMBF) through the West African Science Service Centre on Climate Change and Adapted Land Use (WASCAL). The second author was supported by the South African National Research Foundation (NRF). Computing facility was provided by the Centre for High Performance Computing (CHPC, South Africa) and the Climate System Analysis Group (CSAG, University of Cape Town, South Africa).


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Romaric C. Odoulami
    • 1
    • 2
  • Babatunde J. Abiodun
    • 1
  • Ayodele E. Ajayi
    • 3
    • 4
  1. 1.Climate Systems Analysis Group, Department of Environmental and Geographical ScienceUniversity of Cape TownCape TownSouth Africa
  2. 2.West African Science Service Centre on Climate Change and Adapted Land Use (WASCAL), Graduate Research Program - West African Climate SystemFederal University of TechnologyAkureNigeria
  3. 3.Department of Agricultural and Environmental EngineeringFederal University of TechnologyAkureNigeria
  4. 4.Department of Agricultural and Food EngineeringAfe Babalola UniversityAdo EkitiNigeria

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