Multi-decadal oscillations in the hydro-climate of the Okavango River system during the past and under a changing climate

16 The focus of this paper is to understand the multi-decadal oscillatory component of 17 variability in the Okavango River system, in southwestern Africa, and its potential 18 evolution through the 21 st century under climate change scenarios. Statistical analyses 19 and hydrological modelling are used to show that the observed multi-decadal wet and 20 dry phases in the Okavango River and Delta result from multi-decadal oscillations in 21 rainfall, which are likely to be related to processes of internal variability in the climate 22 system, rather than external natural or anthropogenic forcing. Analyses of changes in 23