Horn of Africa growing drier because of global warming

Nature : The Horn of Africa is experiencing a period of reduced rainfall, most likely linked to anthropogenic climate change. That finding was made by Jessica Tierney of the University of Arizona in Tucson and her colleagues, who collected deep-sea sediment cores drilled from the Gulf of Aden in the Arabian Sea. The researchers used the cores to reconstruct past climate change, because instrumental records for the region are lacking and natural indicators such as lake basins and trees are scarce. From plant material and fossilized microorganisms trapped in the sediment cores, the researchers were able to deduce past aridity and ocean temperatures. Although the region has experienced bouts of drought before, the steadily increasing dryness through the 20th century is unusual, says Tierney. Their finding contradicts earlier studies that associated the drying trend with the natural variability of ocean surface temperatures.