A 19th century hydroclimate chronology for the semi-arid Karoo, South Africa: Droughts and dry periods in perspective

Abstract

The semi-arid central Karoo of South Africa is an important livestock farming region, oftentimes characterized by water scarcity and limited grazing resources. This paper builds on previous research that has predominantly focused on post 19th century Karoo rainfall characteristics. The paper aims to: 1) establish the long-term frequency and longevity of droughts or dry periods; 2) explore spatial hydroclimatic variability across the Karoo during given dry/drought periods; 3) compare the timing and duration of 19th century Karoo droughts with those of neighboring regions to the east (Lesotho) and north (southern Kalahari); 4) establish the possible role of the El Niño Southern Oscillation (ENSO) in drought occurrence across the Karoo-Kalahari-Lesotho region; 5) determine whether the so called ‘global drought’ of 1877-78 is evident in the central Karoo; and 6) place 19th century droughts in a 20th– 21st century context (or visa versa) for the Karoo. Documentary sources were accessed, photographed and digitized from a variety of repositories (Libraries, Museums, and online sites such as READEX). Multi-station instrumental rainfall records (1861–2022) were made available by the Rubidge family at Wellwood farm. Historical droughts (1861–2022) in the Karoo were spatially highly variable in severity. However, severe droughts in the Karoo have decreased in frequency and amplitude (rainfall deficit) between 1861 and the present.