Changes in annual extreme temperature and heat indices in Limpopo province: period 1941–2016

Several climatic indices have been contributed by the scientific community to analyse climate change implications on the environment, society, and economic growth. In this study, daily temperature time series for minimum and maximum temperatures were used to compute 12 extreme climate indices and 2 plant heat resource indices. The indices for the historical period 1941–2016 are computed from the observed temperature records at 10 climate stations within the Limpopo province in South Africa. The time series for the annual heat-related indices were analysed to obtain the climatology and trends for each of the indices per station. In general, statistically significant warming trends, accounting for at least 5 out of the 10 stations for all indices, were observed over the 65-year period. These are except statistically significant cooling trends observed for a few geographically high-lying stations that constitute at least 1 station. The recorded trends in growing degree days and heat stress indices suggest that the majority of stations experienced a gain in the conditions conducive for native plants to grow, while for crops sensitive to temperatures from 25 to 35 °C, the conditions went through a deterioration during the period.