Desert encroachment and the temporal trends of precipitation in Nigeria’s climate zones

Desertification in Nigeria is the southward spread of desert from Northern Nigeria caused by both climatic changes and human influence. The areas being exposed to desertification at the greatest level in recent years are in parts of North of Nigeria, extending from about latitude 8 ^⁰N to 12 ^⁰N or Savanna zone. The Sahara Desert advances from extreme North of Nigeria southwards at an estimated rate of 600 m per annum. This study was aimed at investigating the relationship between desert encroachment from the Sahara and the trend in Nigeria’s precipitation time series for the time period 1900 – 2010. Computer codes were used to identify the zone with the most substantial reduction in mean monthly precipitation; the trend and periodicity in the precipitation time series were obtained for this zone. Results obtained show that the decrease in precipitation in Nigeria over the time period is most prominent in parts of the Savanna vegetation zone – the zone that is mainly influenced by movement of sand dunes southwards from the Sahara Desert and Sahel region. The change in mean monthly precipitation between the pre-1950 and post-1950 periods in the Savanna zone is the greatest among the three climate zones in Nigeria. Phase change materials are proposed to regulate the precipitation and temperature variability arising from this change.