Historical and projected climatic trends in KwaZulu-Natal: 1950–2100

Abstract

The climate of KwaZulu-Natal, South Africa, is evaluated for historical and projected trends in the period 1950–2100. This region lies next to the warm Indian Ocean and experiences an alternating airflow imposed by subtropical easterly and mid-latitude westerly wind belts. Multi-year wet spells have diminished since 2001 and potential evaporation deficits have spread from the Tugela Valley. Although coastal vegetation is greening and sea temperatures in the Agulhas Current are warming (>0.02‧yr⁻¹), there are fewer rain days and less cloud cover. Tropical winds across southern Africa have turned toward Madagascar, re-directing moisture and convection away from KwaZulu-Natal in recent decades. Long-range coupled model projections of monthly rainfall display weak trends over the 21^st century (−0.01 mm‧day⁻¹‧yr⁻¹) which are overshadowed by multi-year fluctuations (r² = 0.04). In contrast, drying trends in potential evaporation are significant (r² =  0.41). Forecasts of seasonal dry spells could mitigate climate change impacts in south-eastern Africa.