Wednesday, January 12, 2011

climate change

Africa's oldest and deepest lake has experienced unprecedented warming during the past century, a trend that scientists say threatens fish stocks that feed millions of people. The surface of finger-shaped Lake Tanganyika, which stretches 420 miles along the Great Rift Valley, is 26 degrees Celsius -- its warmest temperature in 1,500 years. The lake surface experienced its biggest temperature jump -- 2 degrees Celsius -- during the past 90 years, a period corresponding with increased combustion of fossil fuels and emissions of heat-trapping gases.

"A lot of that increase has happened in the last 50 years, so we do believe man-made global warming is responsible," lead scientist Jessica Tierney explained.

A 2006 report from the U.N. Environment Programme estimated that roughly 200,000 tons of fish were harvested annually from the lake, which borders the Democratic Republic of Congo, Burundi, Tanzania and Zambia. The report estimated that the lake's drainage basin is home to about 10 million people; most of the rural population fishes or farms for a living. The lake supports Africa's largest freshwater fishery.

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