A new study has backed up previous reports that climate change has led to a marked reduction in fish yields in East Africa's Lake Tanganyika, and provides evidence that the impact of global warming may be starting to affect local economies.
Catherine O’Reilly from the University of Arizona, United States, and colleagues found that water temperatures in the lake have risen and wind speeds fallen over the past century. Together, these factors have hampered the flow of deep-water nutrients to the upper layers of the lake, reducing the amount of algae and adversely affecting the fish population.
The findings are published in the journal Nature. Together with separate research published last month in Science (see Climate warming reduces tropical lake productivity) they provide strong evidence that "the effect of global climate change on regional temperature has had a greater impact on Lake Tanganyika than have local human activities," says Dirk Verschuren of Ghent University, Belgium, in an accompanying article in Nature.
Fish from the lake provide more than a quarter of the animal protein supply for populations in the countries bordering the lake — Burundi, the Democratic Republic of Congo, Tanzania and Zambia — so the prediction that air temperatures in the region could increase by about 1.5 ºC over the next 80 years suggests that an important food supply may be further compromised.