ghana climate change vulnerability and adaptation assessment

emission scenarios gives a decrease in wet season rainfall of -1.46 ± 10.35 percent by 2050 and -2.19± 15.25 percent by 2080. The variability among the models' precipitation changes is not verydifferent from the inter-annual variability currently experienced in the region. The Northern Regionwhere Tamale is located is the southern-most region in Ghana to show a consistent trend towarddecreased rainfall. Walembelle (northern Guinea Savanna Zone): Forecasted changes in precipitation range from 25percent decreases to 24 percent increases in wet season rainfall. The overall ensemble predictionacross emission scenarios gives a slight decrease in wet season rainfall of -0.42 ± 8.93 percent by2050 and 1.06 ± 11.79 percent by 2080. The variability among the models' precipitation changes isnot very different from the inter-annual variability currently experienced in the region.Bawku (Sudan Savanna Zone): Forecasted changes in precipitation range from 28 percentdecreases to 30 percent increases in wet season rainfall. The overall ensemble prediction acrossemission scenarios gives a slight decrease in wet season rainfall of -0.10 ± 9.63 percent by 2050 and -0.69 ± 12.94 percent by 2080. The variability among the models' precipitation changes is not verydifferent from the inter-annual variability currently experienced in the region.SEA-LEVEL PROJECTIONSThe coastal regions of Ghana may be vulnerable to sea‐level rise, and two different climate modeling effortsare in reasonably close agreement. By the 2090s, sea level is projected by the UNDP-NSCP climate models torise by the following levels relative to the 1980‐1999 sea level: 0.13-0.43 m under SRES B1; 0.16-0.53 munder SRES A1B; and 0.18-0.56 m under SRES A2 (McSweeney et al., no date a). With respect to the 1990mean sea-level, the EPA-NCAP climate modeling (Minia 2008) also projected sea levels to increase. Thoseestimates range from 0.36 m (lower and upper boundaries of 0.16-0.60 cm) in 2010 to 0.35 m (0.16-0.58 m) in2080 (under SRES A1F1).CLIMATE VARIABILITYThe climate of West Africa is subject to considerable variability across a range of space and time scales (Lebelet al., 2000). This variability is linked to variations in the movement and intensity of the ITCZ as well asvariations in the timing and intensity of the West African Monsoon. The most documented cause of thesevariations on an inter-annual timescale is the El Niño Southern Oscillation (ENSO). The West AfricanMonsoon is influenced either during the developing phase of ENSO or during the decay of some long-lastingLa Niña events (Joly and Voldoire, 2009). In general, El Niño (positive sea surface temperature anomalies inthe equatorial Pacific Ocean) is connected to below normal rainfall in West Africa (Janicot et al., 1998). Othersources of variability at decadal, annual and intra-seasonal time scales include land-atmosphere feedbacks(Taylor et al., 1997; Grodsky and Carton, 2001; Douville, 2002) and large-scale circulation features (Matthews,2004; Mournier et al., 2008; Lavender and Matthews, 2009). At intra-seasonal time scales, the West AfricanMonsoon system also exhibits variability, specifically at frequencies of 15 days and 25-60 days (Janicot andSultan, 2001). The longer of these periods is associated with the Madden-Julian Oscillation (a major source ofintra-seasonal variability in the tropical atmosphere with a period of 30-90 days) and variability in the Asiansummer monsoon (Matthews, 2004; Lavender and Matthews, 2009; Janicot et al., 2009).GHANA CLIMATE CHANGE VULNERABILITY AND ADAPTATION ASSESSMENT 35