There is a rising concern about the agents and mechanisms of climate change. The contribution of anthropogenic greenhouse gases to global warming has long been accepted by most scientists, however, the impacts of some natural factors such as cosmic rays, sunspot and geomagnetic activities are yet to be established. This study investigated the effects of cosmic rays on the climate of south-east and south-south parts of Nigeria from 5 meteorological stations in the regions for a period of 48 years (1965-2012). Sunshine hours and relative humidity were used as weather parameters. No particular trend was found in the value of cosmic rays during the period; similarly, the sunshine hours and the relative humidity also produced very irregular patterns. A very low but positive correlation coefficient of 0.3 was found between cosmic rays and sunshine hours with almost no correlation (r = 0.1) between cosmic rays and relative humidity.
Keywords: Climate Change, Cosmic Rays, Relative Humidity, Sunshine Hours