Holocene climatic trends and rhythms in southern Africa

Southern Africa’s unique mid-latitude oceanic position invites broad comparisons with palaeoclimatic records across the PEP III transect including long-distance thermohaline circulation teleconnections. Atmospheric and oceanic circulation systems around Southern Africa (Fig. 1) are linked (Lutjeharms et al. 2001). They interact to influence distribution of biomes including prominence of C₄ and C₃ grasses in the summer-rain and winter rain regions respectively (Vogel et al. 1978; Cowling et al. 1997) (Fig. 2). Climate is dominated by two systems, the westerlies and easterlies (Fig. 1) and shifts in these systems undoubtedly affected the climate history during the Holocene. The generally moderating effect of the oceans, in particular the warm Agulhas western boundary current on the east coast (Lutjeharms et al. 2001), and the semi-arid nature of the region suggests that moisture rather than temperature changes is the more important climate parameter, at least on the Holocene time scale. Furthermore, the cold Benguela upwelling zone and its associated atmospheric circulation system in the South Atlantic is strongly linked to coastal aridity on the west coast.