Remote Sensing and Geographical Information System (GIS) Modelling of Landuse/ Landscape Over and Climate Change in the Derived Savannah Region of Nigeria

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Akintuyi, A.O
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The interaction of landuse/Landcover (LULC) and climate change, to a large extent, involves anthropogenic activities. This interaction has brought about a complex global environmental change which includes biodiversity loss, land degradation, deforestation, afforestation and forest degradation among others. Such change is manifested through the dual nature of landuse/landcover both as causal factor and as effect of climate change. LULC is initiated through human activities such as forest harvesting for logging, fuelwood and charcoal production without forest regeneration of these forest resources, bush fires, overgrazing, as well as urban and agricultural expansion that tends to increase the concentration of greenhouse gases (GHGs). This study was carried out in a delicate ecological zone where the interaction of LULC and climate change could be well appreciated. The zone is an interface between the forest and savannah zones experiencing drastic environmental change as it impacts on desert encroachment and resource conflicts. The study evaluated coupled interaction between LULC and climate change within the derived savannah zone of Nigeria. It assessed the changes in the landuse/landcover patterns for the periods 1972, 1986, 2002 and 2010, and evaluated the variability in rainfall and temperature as the dominant climatic parameters within the study area over the area from 1941 to 2010. In addition, an attempt was made to predict the interaction between LULC and climate change and to estimate the changes in carbon stock resulting from LULCC. The study further employed remote sensing and GIS techniques to interpret and analyse Landsat satellite imageries for the period under study while the multivariate statistical analysis was used to analyse the historical and downscaled climate data for the present and future climates. In predicting the nature of interaction between LULC and climate for future climate within the region, the study adopted both statistical and Land Change Modeller (LCM) techniques. The study revealed that the built up area, farmland, waterbody and woodland experienced a rapid increase of about 1,134.69%, 1,202.85%, 631.51% and 188.09%, respectively, while the forest cover, degraded surfaces and grassland lost about 19.32%, 72.76% and 0.05% respectively between 1972 and 2010. The study thus confirmed the sinusoidal nature of the climatic pattern with 2.03mm (0.02%) and 0.15mm (0.01%) increase per annum for mean annual rainfall and rainfall anomaly respectively with annual mean rainfall of 1,316mm for the present climate. The future climate was predicted to increase at a rate of 3.13mm (0.2%) per annum for mean annual rainfall with an annual mean of 1,393mm. Also, the rainfall variability index duringthe present climate ranges between 15 and 23% and 9 – 13% for future climate, which indicated that rainfall will be more stable in the future climate, while temperature variability indices range from 1.42 – 2.41% and 1.26 – 1.33% for both the present and future climates respectively. Due to the short temperature range predicted for the future climate, temperature will be more stable with higher intensity. Furthermore, the study predicted 40.28% and 37.84% reduction in the forested area between 1986 and 2050 and 2010 and 2050 respectively. In addition, the study estimated that about 298,767,040 tons of CO2 will be emitted due to the deforestation and forest degradation induced by the interaction of LULC and climate. The study concludes that climate parameters, especially rainfall will be the major driver of LULC change within the study area and calls for further studies on the of rainfall variability and change during future climate.
A Thesis Submitted to the School of Postgraduate Studies, University of Lagos
Akintuyi, A.O (2015). Remote Sensing and Geographical Information System (GIS) Modelling of Landuse/ Landscape Over and Climate Change in the Derived Savannah Region of Nigeria. A Thesis Submitted to University of Lagos School of Postgraduate Studies Phd Thesis and Dissertation, 245pp.