Long-term trends and variability in the dryland microclimate of the Northern Cape Province, South Africa

A wealth of information on the extent and severity of global climate change has been produced through research over the past few decades. Global trends of the climate should be observable at a regional and local level, yet certain areas remain under-represented in both national and international research. This study presents an investigation into the microclimatic trends of the semi-arid/arid environment of the Northern Cape Province, South Africa. Long-term (1982-2016) historical daily meteorological data were analyzed using the RClimDex software package as well as other multi-temporal regression analyses. Results indicate an overall warming of the study sites, with rates of change varying between 1 and 4 degrees C century(-1). The overall increase in annual average air temperature observed at the three sites is linked to daytime warming trends. Total annual rainfall, as well as atmospheric water vapor, was found to be decreasing at significant rates across the sites, with serious implications for livestock agriculture in the region. Model outputs of normalized difference vegetation index (NDVI), 0-100-mm soil water and the reflection coefficient, indicate that observed changes in the microclimate are not a consequence of terrestrial factors. The results of the study indicate that the microclimate of the dryland Northern Cape environment is changing but at rates that are different to global and continental estimates. The study highlights the need for local climate change investigations, and also identifies limitations in using only ground-based datasets.