Intensification of the Southern Hemisphere westerly winds during the last deglaciation (18.5–14.0 cal ka BP): Evidence from Pearly Beach wetland on the southern Cape coast of South Africa

ABSTRACT The southwestern Cape of South Africa experiences a complex and dynamic climate, shaped by the interplay between the temperate Southern Hemisphere westerly winds and the subtropical easterlies. Despite the climatic sensitivity of the region, relatively few studies have examined how conditions have varied since the last deglaciation in response to significant changes in global boundary conditions. Here, we present a 30 000‐year sedimentary record from a coastal wetland at Pearly Beach on the southern Cape coast, focusing on climatic changes that occurred during the last glacial–interglacial transition. Downcore variations in grain size and inorganic geochemical composition provide evidence for a period of heightened storm activity between ~18.5 and 14.0 cal ka BP, which we interpret to reflect intensified westerly wind‐driven activity. This period of increased storminess coincides with a slowdown in Atlantic meridional overturning circulation (AMOC) during Heinrich Stadial 1 (HS1: ∼18–14.6 ka) and subsequent warming in the southeast Atlantic Ocean. We propose that this warming enhances moisture uptake by westerly frontal systems, leading to stronger storms in the southern Cape. The intensification of westerly‐driven storms occurred concurrently with a broader cooling trend across South Africa, suggesting that AMOC variability during HS1 may have influenced climate across much of the region.