NEW YORK, April 16 (UPI) -- Mud layers and dead trees preserved at the bottom of a lake in Ghana show a pattern of devastating droughts in West Africa, U.S. scientists say.
Researchers who studied Lake Bosumtwi said that the droughts that appear to be linked to weather cycles in the Atlantic occur every 30 to 65 years, The New York Times reported. But they also found evidence of much longer droughts, the most recent one lasting from 1400 to 1750.
While their evidence of drought patterns over the past 3,000 years comes from one lake, the team said there is other evidence that the patterns affect a wide area where millions of people now live. Most of them are poor, living in rural areas where they depend on farming small plots for subsistence.
The report by a team headed by Timothy M. Shanahan of the University of Texas at Austin and Jonathan T. Overpeck of the University of Arizona was published Friday in Science.
Kevin Watkins, director of the U.N. Human Development Report office, said that even a delay in the arrival of the rainy season can mean catastrophe for many African farmers.
