Projected temperature increases over southern Africa due to increasing levels of greenhouse gases and sulphate aerosols

Two transient climate change integrations from the Hadley Centre fully-coupled ocean-atmosphere general circulation model are considered. In the first experiment, climate is forced by greenhouse gases only. In the second experiment, the direct effects of sulphate aerosols in addition to greenhouse gases are included. Both experiments simulate mean temperature and temperature variability over southern Africa, during the period 1961-1990, which are not statistically significantly different from observations. Over southern Africa, warming predicted in the sulphate experiment for the decade during which carbon dioxide doubled (2050-2059), expressed relative to 1990-1999, was 2.1 degree C, as opposed to 3.7 degree C in the greenhouse gas only experiment. The rate of warming over southern Africa for the seven decades between 1990 and 2059 was 0.47 degree C per decade in the greenhouse gas and 0.3 degree C per decade in the sulphate aerosol experiments. In both cases, the rate of warming over southern Africa was greater than the global average.