How severe can climate change become in a warming world? Worse than anything we’ve seen in written history, according to results of a study. An international team of scientists has compiled four dozen paleoclimate records from sediment cores in Lake Tanganyika and other locations in Africa. The records show that one of the most widespread and intense droughts of the last 50,000 years or more struck Africa and Southern Asia 17,000 to 16,000 years ago.