Comparative Assessment of Climatic Variability across Rivers and Bayelsa States of Nigeria

This research evaluates long-term climatic variability across Rivers and Bayelsa States of Nigeria. A 65-year data set (1958–2023) comprising rainfall and temperature records obtained from the Climatic Research Unit (CRU) and the Nigerian Meteorological Agency (NIMET) was analyzed using statistical and geospatial techniques, including Mann–Kendall, Spearman’s Rho, linear regression, and GIS mapping. Results reveal a statistically significant decreasing trend in rainfall and a corresponding increasing trend in temperature across states at a significance level of α < 0.01. Change point analysis indicates major shifts in rainfall and temperature patterns around the early 1980s. The first climatic period (1958–1987) recorded higher rainfall and lower temperature variability compared to the second period (1988–2023), which showed reduced rainfall and elevated temperature levels. Seasonal analysis further confirms declining rainfall and increasing temperature trends, with implications for water resource availability, flood risk, and agricultural productivity. The study highlights the growing vulnerability of Nigeria’s coastal regions to climate change and underscores the need for adaptive water resource management strategies.