Future impacts of global warming and reforestation on drought patterns over West Africa
- 617 Downloads
This study investigates how a large-scale reforestation in Savanna (8–12°N, 20°W–20°E) could affect drought patterns over West Africa in the future (2031–2060) under the RCP4.5 scenario. Simulations from two regional climate models (RegCM4 and WRF) were analyzed for the study. The study first evaluated the performance of both RCMs in simulating the present-day climate and then applied the models to investigate the future impacts of global warming and reforestation on the drought patterns. The simulated and observed droughts were characterized with the Standardized Precipitation and Evapotranspiration Index (SPEI), and the drought patterns were classified using a Self-organizing Map (SOM) technique. The models capture essential features in the seasonal rainfall and temperature fields (including the Saharan Heat Low), but struggle to reproduce the onset and retreat of the West African Monsoon as observed. Both RCMs project a warmer climate (about 1–2 °C) over West Africa in the future. They do not reach a consensus on future change in rainfall, but they agree on a future increase in frequency of severe droughts (by about 2 to 9 events per decade) over the region. They show that reforestation over the Savanna could reduce the future warming by 0.1 to 0.8 °C and increase the precipitation by 0.8 to 1.2 mm per day. However, the impact of reforestation on the frequency of severe droughts is twofold. While reforestation decreases the droughts frequency (by about 1–2 events per decade) over the Savanna and Guinea coast, it increases droughts frequency (by 1 event per decade) over the Sahel, especially in July to September. The results of this study have application in using reforestation to mitigate impacts of climate change in West Africa.
KeywordsWest African monsoon Droughts SPEI Reforestation Self-organizing maps WRF RegCM
This study was supported by the West African Service Center for climate change and Land use Adapted (WASCAL). Computation supports were provided by the Climate Sciences Analysis Group (CSAG, UCT) and the Centre for High Performance Computing (CHPC, South Africa). The African Centre of Meteorological Applications for Development (ACMAD) supported the first author through the ISACIP project. The second author was supported by the National Research Foundation in South Africa.
- Abiodun BJ, Salami AT, Mathew OJ, Odedokun O (2013) Potential impacts of afforestation on climate change and extreme events in Nigeria. Climate Dynamics DOI. doi: 10.1007/s00382-012-1523-9 7
- Afiesimama EA, Pal JS, Abiodun BJ, Gutowski WJ, Adedoyin A (2006) Simulation of West African monsoon using the RegCM3. Part I: model validation and interannual variability. Theor Appl Climatol 86:23–37Google Scholar
- Araujo JA, Abiodun BJ, Crespo O (2016) Impacts of drought on grape yields in Western Cape, South Africa. Theor Appl Climatol 123(1-2):117–130Google Scholar
- Browne NAK, Sylla MB (2012) Regional climate model sensitivity to domain size for the simulation of the West African summer monsoon rainfall, International Journal of Geophysics, vol. 2012, Article ID 625831, 17 pages. Doi: 10.1155/2012/625831.
- Compo GP, Whitaker JS, Sardeshmukh PD, Matsui N, Allan RJ, Yin X, Gleason BE, Vose RS, Rutledge G, Bessemoulin P, Brönnimann S, Brunet M, Crouthamel RI, Grant AN, Groisman PY, Jones PD, Kruk MC, Kruger AC, Marshall GJ, Maugeri M, Mok HY, Nordli O, Ross TF, Trigo RM, Wang XL, Woodruff SD, Worley SJ (2011) The twentieth century reanalysis project. Quarterly J Roy Meteorol Soc 137:1–28. doi: 10.1002/qj.776
- Dai A (2011) Drought under global warming: a review. Wiley Interdisciplinary Reviews. Climate Change 2(1):45–65Google Scholar
- Diallo I, Sylla MB, Giorgi F, Gaye AT, Camara M (2012) Multi-model GCM-RCM ensemble based projections of temperature and precipitation over West Africa for the early 21st century. International Journal of Geophysics.Google Scholar
- Diasso U, Abiodun BJ (2015) Drought modes in West Africa and how well CORDEX RCMs simulate them. Theoretical and Applied Climatology pp 1–18: DOI 10.1007/s00704-015-1705-6.
- Dickinson RE, Henderson SA, Kennedy PJ (1993) Biosphere-Atmosphere Transfer Scheme (BATS) version 1E as coupled to the NCAR Community Climate Model. NCAR Tech. rep. TN-387+STR, 72 pp.Google Scholar
- Giorgi F, Coppola E, Solmon F, Mariotti L, Sylla MB, Bi X, Elguindi N, Diro GT, Nair V, Giuliani G, Cozzini S, Guettler I, Brien O, Tawfik T, Shalaby A, Zakey A, Steiner AS, Stordal A, Sloan F, Brankovic L (2012) RegCM4: model description and preliminary tests over multiple CORDEX domains. Clim Res 52:7–29CrossRefGoogle Scholar
- Hewitson BC (2001) Global and regional climate modelling: application to Southern Africa. Water Research Commission 806/1/01, PretoriaGoogle Scholar
- Hewitson BC, Crane RG (1996) Climate downscaling techniques and applications. Clim Res 7:85–95Google Scholar
- Holtslag AA, De Bruijn EI, Pan H (1990) A high resolution air mass transformation model for short-range weather forecasting. Mon Weather Rev 118:1561–1575. doi: 10.1175/1520-0493(1990)118<1561:AHRAMT>2.0.CO;2
- Hong SY, Dudhia J, Chen SH (2004) A revised approach to ice microphysical processes for the bulk parameterization of clouds and precipitation. Mon Weather Rev 132:103–120Google Scholar
- Hong SY, Noh Y, Dudhia J (2006) A revised approach to ice microphysical processes for the bulk parameterization of clouds and precipitation. Mon Weather Rev 132:103–120. doi: 10.1175/1520-0493(2004)132<0103:ARATIM>2.0.CO;2
- Hudson DA (1998) Antarctic Sea ice extent, southern hemisphere circulation and South African rainfall. PhD thesis, University of Cape Town.Google Scholar
- IPCC (2007a) Climate Change 2007: The physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USAGoogle Scholar
- IPCC (2007b) Contribution of working group III to the fourth assessment report of the Intergovernmental Panel on climate change [Metz B., Davidson O.R., Dave R. and Meyer L.A. (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA.Google Scholar
- IPCC (2012) Managing the risks of extreme events and disasters to advance climate change adaptation. A Special Report of Working Groups I and II of the Intergovernmental Panel on Climate Change [Field, C.B., V. Barros, T.F. Stocker, D. Qin, D.J. Dokken, K.L. Ebi, M.D. Mastrandrea, K.J. Mach, G.-K. Plattner, S.K. Allen, M. Tignor, and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, UK, and New York, NY, USA, 582 pp.Google Scholar
- IPCC (2013): Climate Change 2013: the physical science basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp, doi: 10.1017/CBO9781107415324.
- IPCC (2014) Climate Change 2014: impacts, adaptation, and vulnerability. Part B: Regional Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Barros, V.R., C.B. Field, D.J. Dokken, M.D. Mastrandrea, K.J. Mach, T.E. Bilir, M. Chatterjee, K.L. Ebi, Y.O. Estrada, R.C. Genova, B. Girma, E.S. Kissel, A.N. Levy, S. MacCracken, P.R. Mastrandrea, and L.L. White (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 688 pp.Google Scholar
- Jones CD, Hughes J, Bellouin N, Hardiman S, Jones G, Knight J, et al. (2011) The HadGEM2-ES implementation of CMIP5 centennial simulations. Geosci Model Dev 4:543–570. doi: 10.5194/gmd-4-543-2011
- Kiehl JT, Hack JJ, Bonan GB, Boville BA, Briegleb BP, Williamson DL, Rasch PJ (1996) Description of the NCAR Community Climate Model (CCM3). NCAR Tech. Note 4201STR, 152 pp.Google Scholar
- Klein C, Heinzeller D, Bliefernicht J, Kunstmann H (2015) Variability of West African monsoon patterns generated by a WRF multi-physics ensemble. Clim Dyn. doi: 10.1007/s00382-015-2505-5
- Meehl G et al (2007) Global climate projections Climate Change 2007: The Physical Science Basis ed S Solomon (Cambridge: Cambridge University Press) pp 747–845Google Scholar
- Meque A, Abiodun BJ (2015) Simulating the link between ENSO and summer drought in southern Africa using regional climate models. Clim Dyn 44(7-8):1881–1900Google Scholar
- Mlawer EJ, Taubman SJ, Brown PD, Iacono MJ, Clough SA (1997) Radiative transfer for inhomogeneous atmospheres: RRTM, a validated correlated-k model for the longwave. J Geophys Res 102. doi: 10.1029/97JD00237
- Monerie PA, Fontaine B, Roucou P (2012) Expected future changes in the African monsoon between 2030 and 2070 using some CMIP3 and CMIP5 models under a medium-low RCP scenario. Journal of Geophysical Research D: Atmospheres, 117(16).Google Scholar
- New M, Hewitson B, Stephenson DB, Tsiga A, Kruger A, Manhique A, Gomez B, Coelho CAS, Masisi DN, Kululanga E, Mbambalala E, Adesina F, Saleh H, Kanyanga J, Adosi J, Bulane L, Fortunata L, Mdoka ML, Lajoie R (2006) Evidence of trends in daily climate extremes over southern and west Africa. J Geophys Res 111:D14102. doi: 10.1029/2005JD006289 CrossRefGoogle Scholar
- Reij C (1983) L’évolution de la lutte anti-érosive en Haute Volta: Vers une plus grande participation de la population. Institute for Environmental Studies, Vrije University, Amsterdam, the Netherlands.Google Scholar
- Skamarock WC, Klemp JB, Dudhia J, Gill DO, Barker DM, Duda MG, Huang X-Y, Wang W, Powers JG (2008). A Description of the Advanced Research WRF Version 3. NCAR Tech. Note NCAR/TN-475+STR.Google Scholar
- Smirnova T, Brown J, Benjamin S, Kim D (2000). Parameterization of cold-season processes in the MAPS land-surface scheme. J Geophys Res 105:4077–4086Google Scholar
- Tewari M, Chen F, Wang W, Dudhia J, LeMone MA, Mitchell K, Ek M, Gayno G, Wegiel J, Cuenca RH (2004) Implementation and verification of the unified NOAH land surface model in the WRF model. 20th conference on weather analysis and forecasting/16th conference on numerical weather prediction, pp. 11–15.Google Scholar
- Ujeneza EL, Abiodun BJ (2015) Drought regimes in southern Africa and how well GCMs simulate them? Clim Dyn 44(5-6):1595–1609Google Scholar