Temperature variations as evidence of climate change in northern Nigeria
The paper seeks to investigate whether evolving temperature patterns over northern Nigeria agree with the projections made by global warming and climate change models. The data used are screen air temperature on a monthly time scale. These data were obtained from the database of the Nigerian Meteorological Agency (NIMET). The location of the stations adequately represents a fair coverage of the study area. Descriptive statistics of the long-term characteristics of temperature were computed for all the stations. Dispersion and variability indices (standard deviation and coefficient of variation) were also calculated for all the sampled stations. The derived long-term properties of temperature for the region were mapped out using Geographic Information System (GIS) software. Computer-generated graphs were also plotted for the long-term monthly as well as seasonal/annual temperature characteristics. Furthermore, temperature Anomaly values were computed for all the stations. Time series for each station as well as regionally averaged values for the respective ecological zones were plotted in order to present the inter-annual characteristics of temperature for the study area. Trends and discontinuities in temperature time series for northern Nigeria were analyzed using 5-year moving averages and regression. Results obtained from the study indicates variability in annual temperature totals is lower than those of onthly totals; temperature time series present an irregular increase; annual temperature is characterized by a quasi-generalized increase for all stations and a general increase in temperatures for all stations since the 1950s.This increase related to observations at the regional scale were also compared with the IPCC temperature models. The results obtained were found to have similar trends with those of the models. This serves as a pointer to the existence of global warming and climate change phenomenon in northern Nigeria. The study recommends that further research directed at addressing gaps in existing knowledge on global warming and climate change should be encouraged as this would reduce uncertainties and thus facilitate informed decision-making related to issues bordering on climate change.
Keywords: Dispersion, inter-annual, long-term, temperature, variability