Desertification risk analysis and assessment in Northern Nigeria

Abstract

Changes in climatic conditions and human activities have led to increase in surface temperature, potential evapotranspiration and decrease in rainfall, thereby increasing desertification risk in the study area. Data used included Landsat images and meteorological data (1984–2015). Land use land cover change (LULCC) was estimated using maximum likelihood supervised classification. Land surface temperature (LST) was computed from thermal bands while desertification risk index was calculated using meteorological data from 5 weather stations and Normalized Differential Index (NDVI) values. The results from the LULCC revealed a significant reductions in rangeland by 13,418 Km2; while water body and rock out-crop were also affected by 1255 Km2 and 2592 Km2 respectively. The result also showed built-up and barren land with increase estimated at 5755 Km2 and 2016 11,512 Km2 respectively. LST increased by 2.8 °C from 1984 to 1999 and 2.7 °C from 1999 to 2014 with values at 43.8 °C in 1984, 46.6 °C in 1999 and 49.3 °C in 2015. A similar trend was observed from climatic data obtained while reduction in amount of rainfall was recorded over the years. Desertification Risk Index (DRI) was used to identify areas at risk with notable increase in 2014 encroaching south-ward. Desertification risk between 1984 and 1999 recorded the least threat with 1.32 and 8.53 as the lowest and highest risk rate while in 2014 it increased with the highest at 9.1 and the least value of 1.97. The results of the study show that desertification in Bauchi State is evident due to the rapid changes in climatic conditions and anthropogenic activities.