Environmental desiccation hypothesis

The information collected by missionaries and explorers influenced some theories of environmental changes in Africa. The hypothesis of progressive environmental desiccation began to attract scholarly attention by 1900. The theory was reinforced by the prevalence of extended and frequent droughts.41 David Livingstone based his postulation of the desiccation of the African environment on oral sources and his field observations of dry streams and shrinking and drying lakes in East and Central Africa. Presuming that the African environment was gradually drying up led to speculation about whether African populations could survive or perhaps even die out. Alfred Sharpe42 added that East Africa might be undergoing desiccation.

While there was no scientific basis for these predictions, those endorsing the postulations alleged that they were reinforced by African people’s reliance on rainmakers. The rainmakers supposedly possessed supernatural powers to make rains to fall. The European argument was that if the environment were not drying up, the rainmakers would not be needed. It was a popular theory and believed to be true, although it was unsubstantiated by journal accounts.

The first source of the desiccation theory is the environmental and climatic data collected by missionaries at their stations and on their travels. The second source is found in their reports of indigenous knowledge of environmental and climate change. For example, David Livingstone relied on the terminology of landscapes used by African people, such as ‘dry river valleys,’ which he interpreted to mean that waters had flowed through them earlier and had since ceased. Nonetheless, no historical chronology was given of when such changes might have occurred. Conversely, African societies also associated the drying up of the land with the arrival of white people in their territories—regarding it as a bad omen. The missionaries dismissed the African belief in rainmaking and the connection between the arrival of white people and dry periods as myths. In this context, it is there- fore surprising that the information provided by African informants was accepted as accurate about environmental desiccation. The desiccation theory ignored the evidence that the climate of Africa fluctuated between dry and wet episodes, as opposed to describing progressive changes from wetter to drier conditions.4

Georgina Endfield and David Nash44 evaluated the veracity of the theory of desiccation, using original, unpublished sources in the archives of the London Missionary Society. The authors reconstructed the purported environmental changes using the historical chronology in the sources and found no evidence that supported the theory. The authors contend that ‘the observational basis of the entire argument for desiccation in Africa may be untenable.’45 What geographical science lacked in predictive power it therefore gained from observation and spatial analysis. In the next section, we use European textual narratives to reflect on spatial analysis of African environments during the middle and late nineteenth century.

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