Derive Precipitation Effectiveness Indices as Evidence of Climate Change and Implications on Food Security in JOS South Local Government Area of Plateau State, Nigeria

The focus of this study is to examine changes in precipitation effectiveness indices to show evidence of climate change in Jos South Local Government Area of Plateau State. Fifty years� daily Precipitation data (1966-2015) for Jos south LGA were used to derive six important Precipitation Effectiveness Indices: onset, cessation and length of rainy season, annual rainfall, rainfall amount in months of growing season (April to October) and occurrence of pentad dry spells (5, 10 and 15days). The derived indices were subjected to time series analysis to determine the trend in their occurrences in the face of the current global climate change. Trend lines and linear trend line equations for each of the parameters were fitted to show the direction of change. Results of analysis showed that mean onset date was 15th of April while mean cessation date was 25th of September. This implies that the rainy season starts early in recent times while cessation dates arrive late. Consequently, the length of rainy season is long. This showed that the trend of onset and cessation dates and length of rainy season are characterized by marked variability. Additionally, long term mean rainfall was 1266.54 mm. Maximum rainfall occurred in 1969 (1720.3 mm) while the minimum was 814 mm in 1995. Results revealed more incidences of single pentad dry spells occurring all through the period compared to 10 and 15 consecutive dry spells. This implies that dry spells of 5 days were common while dry spells of 10 days and 15 consecutive days were fewer. This implies a decline in precipitation; its intensity, amount and duration in Jos South. These are all indications of climate change syndrome. It can be recommended that continuous data acquisition should be encouraged in areas where none existed, public enlightenment on the impacts of climate change, adopting new hybrids of short-duration crop varieties in cases of fluctuating trends, early planting and establishment of dam sites will minimize impacts of these changes on livelihood.