ghana climate change vulnerability and adaptation assessment

use of an ensemble of models helps limit the influence of any bias present in any one model. Temperatureand precipitation data are available from http://www.climatewizard.org .It should be noted that most GCMs have difficulty correctly reproducing a number of key features of theatmospheric circulation patterns over West Africa which contribute to uncertainty in estimates of futurerainfall (Douville et al., 2006; Joly et al., 2007; Caminade and Terray, 2009). Neither the Third nor FourthAssessment Report of the IPCC reached a consensus regarding the sign or magnitude of predicted changes inprecipitation over West Africa during this century (Hulme et al., 2001; Bernstein et al., 2007). The WestAfrican Monsoon is difficult for coarse resolution GCMs to describe considering the wide range ofmechanisms for variability acting at various time and space scales from global teleconnection patterns relatedto the El Nĩno-Southern Oscillation ENSO (Caminade and Terray, 2010) or the Atlantic Multi-DecadalOscillation (Shanahan et al., 2009) to the coupling of soil moisture to intra-seasonal variability (Lavender etal., 2010). Druyan (2010) provides a convincing argument for the need of more detailed (higher resolution)modeling to properly capture critical processes in this region. For this reason we focus on the changespredicted by an ensemble of climate models as this provides a means of examining not only the projectedchange in temperature and precipitation but also provides a measure of confidence in these projections.TEMPERATURE PROJECTIONSFrom country-wide projections for Ghana (McSweeney et al., no date a), the mean annual temperature isprojected to increase by 1.0 to 3.0°C by the 2060s and 1.5 to 5.2°C by the 2090s. The range of projections bythe 2090s under any one emission scenario used in the UNDP-NSCP work is about 1.5‐2.5°C. The projectedrate of warming is more rapid in the northern inland regions of Ghana than the coastal regions (McSweeneyet al., no date a). All projections indicated substantial increases in the frequency of days and nights that areconsidered “Hot” in current climate, but the range of projections between different models was large.Annually, projections indicated that “Hot” days will occur on 18‐59 percent of days by the 2060s and 25‐90percent of days by the 2090s. Days considered “Hot” by current climate standards for their season mayincrease most rapidly in July through September occurring on 34‐99 percent of days of the season by the2090s. Nights considered “Hot” for the annual climate of 1970‐99 are projected to occur on 28‐79 percent ofnights by the 2060s and 39‐90 percent of nights by the 2090s. Nights considered “Hot” for each season by1970‐99 standards are projected to increase most rapidly in July through September occurring on 52‐99percent of nights in every season by the 2090s. Most projections indicated decreases in the frequency of daysand nights considered “Cold” in the current climate. “Cold” days and nights are projected to occur on