Geography
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Item Hydrological responses to climate and land use changes: the paradox of regional and local climate effect in the Pra River Basin of Ghana(Elsevier Ltd., 2020) Bessah, E.; Raji, A. O.; Taiwo, O. J.; Agodzo, S. K.; Ololade, O. O.; Strapasson, A.Study Region: Pra River Basin, Ghana. Study Focus: The study modelled the changes in water yield using regional, sub-regional and local climate conditions from modelling outputs at spatial resolutions of 44 km, 12 km and 0.002 km respectively to drive the Integrated Valuation of Ecosystem Services and Trade-offs model at three time periods of land use land cover (LULC). Changes in historical water yield (simulated for 1986, 2002 & 2018 LULC using the mean climatic parameters from 1981-2010) and future scenario (simulated for 2018 LULC using the mean climatic parameters from 2020-2049) for annual, seasonal and monthly periods were assessed. New Hydrological Insights for the Region: The results show that future annual water yield could change by -46%, -48%, +44% and -35% under the regional, sub-regional, local and ensemble mean of the climate scenarios respectively. Seasonal water yield from the ensemble mean of the future climate scenario was projected to decrease between 2-16 mm, with a mean decrease of 33.39% during the December–February season. There was no directional effect of spatial resolution on water yield. The future period could be impacted by both drought and flood. We recommend that re/afforestation should be encouraged to improve infiltration and reduce deforestation which was 2.27% per annum in the assessed period to prevent flood causing runoffs, while irrigation technology will help to improve resilience to drought.Item The impact of varying spatial resolution of climate models on future rainfall simulations in the Pra River Basin (Ghana)(IWA Publishing, 2020) Bessah, E.; Raji, A. O.; Taiwo, O. J.; Agodzo, S. K.; Ololade, O. O.This work compares future projections of rainfall over the Pra River Basin (Ghana) using data from five climate models for the period 2020–2049, as referenced to the control period 1981–2010. Bias-correction methods were applied where necessary and models’ performances were evaluated with Nash–Sutcliffe Efficiency, root-mean-square error and coefficient of determination. Standardised Anomaly Index (SAI) was used to determine variability. The onset and cessation dates and length of the rainy season were determined by modifying the Walter–Olaniran method. The ensemble means of the models projected a 1.77% decrease in rainfall. The SAI showed that there would be drier than normal years with the likelihood of drought occurrence in 2021, 2023, 2031 and 2036. The findings showed that high-resolution models ( 25 km) were more capable of simulating rainfall at the basin scale than mid-resolution models (26–150 km) and projected a 20.13% increase. Therefore, the rainfall amount is expected to increase in the future. However, the projected increase in the length of the dry season by the ensemble of the models suggested that alternative sources of water would be necessary to supplement rainfed crop production for food security.Item Perceived causes, exposures and adjustments to seasonal heat in different residential areas in Ibadan, Nigeria(Springer, 2012) Taiwo, O. J.; Olaniran, H. D.; Osayomi, T.Local perception can be an important resource for assessing and managing climate-related extremes and identifying adjustment strategies unique to specific settings. The objectives of the study are two-fold. Firstly, it examined the perceived causes, exposures and adjustments to seasonal heat events using different residential density areas of Ibadan, Nigeria, as spatial units of analysis. Secondly, it investigated the relationship between heat exposure, built environment, socio-economic and cultural factors. Results show that intense heat from the sun, climate change and absence of rains, among others, was identified as perceived causes. Number of electricity hours, distance from water supply points and the number of neighborhood trees were listed as the three most important factors affecting heat exposure. In addition, there were considerable variations in the perceived causes (F = 4.86, p<0.05), in exposures (F = 3.61, p<0.05), and in adjustments to seasonal heat (F = 8.75, p<0.05) across different residential density areas in Ibadan, Nigeria. The study demonstrates that local knowledge based on the perceptions, exposures and adjustments to seasonal heat waves has the potential in some cases to provide valid inputs into vulnerability and adaptation assessments.Item Impacts of abandoned Gebu Forest escarpment reserve in Kogi State of Nigeria on climate change: need for forest institutional measures(Ecological Society of Nigeria, 2010) Agbeja, B. O.; Taiwo, O. J.The study examines abandoned Gebu Forest Escarpment Reserve (GFER) in Kogi State, Nigeria with a view to recommending forest institutional measures for climate change mitigation. The method used for the study was socio-economic survey to gather data through digital mapping, observations, administration of questionnaire and the use of secondary data. The results indicated that the built-up area; mosaic of farmlands/settlements; riparian forest; and wooded savanna within the forest reserve occupy 7.13%, 25.07%, 44.17% and 23.63% respectively. A total of estimated 5,413,216 kg of CO2 is lost to the atmosphere per year in GFER as a result illegal occupation of the community people within the forest reserve. The forest reserve has a composition of trees that are predominantly of savanna species. The respondents (76.67%) were aware of the GFER and majority of the respondents affirmed their livelihood dependency on Gebu forest reserve for farming, grazing, hunting, sales of forest products and collection of fuelwood for energy. The causes of anthropogenic activities of the communities within and around the GFER include absence of forest management by the State Forestry Department; high population growth and unsustainable agricultural practices while the effects of these activities include increase in environmental temperature, flooding, dryness of watershed and droughts. The binary logistic model for institutional measures for climate change mitigation of GFER in Kogi State indicated overall significant fit to the data judging from the chi square value (df, 7 ) =143.62 that is significant at p<0.05. The final loss of the model indicated a value of 7.58. It is recommended that a New Forest Management Plan should be produced for a good tenet of Gebu Forest Escarpment Reserve Management; the Government of Kogi State should enunciate robust forest policy and be complimented with an enactment of forestry act; and secondary forest road should be constructed within and near the forest reserve for easy accessibility, policing, motoring and evaluation of the forest reserve.