Africa's Lake Chad shrinks due to irrigation demands & climate change
Friday, March 02, 2001
Goddard Space Flight Center News
In the 1960s, North central Africa's Lake Chad was larger than the state of Vermont but is now smaller than Rhode Island. NASA-funded researchers using computer models and climate data now understand why Africa's freshwater Lake Chad has been disappearing over the last 30 years.
Michael T. Coe and Jonathan A. Foley of the University of Wisconsin-Madison cite a drier climate and high agricultural demands for water as reasons why what was once one of Africa's largest freshwater lakes is shrinking. "Lake Chad was about 25,000 square kilometers in surface area back in 1963," Foley noted. Now the lake is about one-twentieth the size it was in the mid 1960s.
Their paper titled "Human and Natural Impacts on the Water Resources of the Lake Chad Basin," is being published today in the American Geophysical Union's Journal of Geophysical Research. In their paper, Coe and Foley used an integrated biosphere model (IBIS) with long time-series climate data. They simulated the exchange of energy, water and carbon dioxide between vegetation, soil and the atmosphere, and tracked the changes in Lake Chad since 1953. They input the data from the biosphere model into a hydrological model and were able to estimate changes in river discharge, the amount of water in wetlands and in Lake Chad.
"NASA’s Landsat satellite imagery taken of the lake over the last 30 years really capture the model conclusions and visualize them very well," the researchers noted.
For the complete article, go to: http://www.gsfc.nasa.gov/GSFC/EARTH/environ/lakechad/chad.htm