Irregular rainfall is the primary reason for severe crop yield reductions in the Sahel of West Africa, with sometimes very serious consequences for society and national economies. To that extent recent drought events in the Sahel have overprinted their rhythms, causing widespread dislocation to human beings and their economic activities. Accordingly, this study provides a procedure for predicting future crop yield trends using scenarios of climatic events. In the process, models which relate rainfall to agricultural yields were constructed for three sites in Northern Nigeria. The models were constructed for a 17-year period spanning 1969-1985, the severe drought years. In all cases, the model input variables were rainfall and crop yield data. All the models were tested for their predictive capabilities using crop yield data for 1986-2006. In order to assess the potential effects of drought on agricultural yields in the West African Sahel, the study created scenarios of future climatic changes based on arbitrary data and analogues of historical climatic data. The results indicated that a possible climatic change which involves up to 50% reduction in the mean rainfall for locations in the West African Sahel will reduce yields substantially and in many cases could lead to total crop failure. The study concludes that scenario experiments are useful tools in guiding farmers on adjustment options during drought events. Additionally, supplementary irrigation schemes must be pursued vigorously by all stakeholders if farming is to remain lucrative in the region.

The study assessed the potential impact of forest conversion for micro-climate as well as the implications of micro-climate alteration for floral diversity in a humid forest region of South Eastern Nigeria. The measurement of possible micro-climate condition was taken at two sites including forest under-storey and the nearest open space, cleared but under three year fallow, while the number of trees, shrubs and herbs was documented and species diversity index determined. Three climate parameters were taken into consideration: rainfall, temperature and relative humidity. Results showed that the quantity of rain in open space was higher than in the forest under-storey, implying exposure to possible accelerated runoff, loss of valuable top soil and alteration of floral diversity. Mean daily temperature was lower under forest cover than open space, but with a higher range in the under-storey. At the same time, difference between maximum and minimum temperature was lower in the forest under-story. Relative humidity was higher in forest under-storey than open space; being highly variable between morning and evening in the open space. The conversion of forest has implications for traditional livelihood, which is dependent on forest products. This was expressed in the variation in the floral diversity across the land cover types. Strategies for alternative livelihoods should be explored for local communities.