Extreme floods around ad 1700 in the northeern Namib Desert, Namibia, and in the Orange River catchment, South Africa - were they forced by a decrease of solar irradiance during the Little Ice Age?

Abstract

We review recent advances in the study of palaeofloods and in the reconstructions of climate features from sedimentary archives in the Namib Desert. Global environments are known to have varied over the past millennia, but the spatial patterns of these variations have remained poorly understood. We used palaeoflood sediments to reconstruct rainfall patterns over the last 500 years (Little Ice Age). During the Little Ice Age, the northern Namib Desert and the Orange River catchment experienced palaeofloods that exceeded those of the millennium prior and of the two centuries since. During the last two centuries, floods remained well below the Little Ice Age maximum levels. The patterns of hydrological changes imply dynamic responses of rainfall to solar irradiance forcing changes involving the Benguela El Nino oscillation.