Agricultural expansion in Africa could cause climate change
Marc Parlange, a co-author of the study and a hydrology specialist and professor of civil engineering at the University of British Columbia in Vancouver, Canada, discovered that a Burkina Faso savannah received more rainfall than nearby land cleared for agriculture, posing serious questions about the sustainability of current farming practices in semi-arid regions.
Burkina Faso, one of the poorest countries in West Africa, urgently needs to improve agricultural production to support its population of 16 million.
"We wanted to understand what happens to rainfall, runoff and groundwater levels when you transform a savannah into agricultural land, something that's happening more frequently as West Africa tries to produce more food," said Parlange.
"We found that the agricultural fields would receive some 10 to 15 percent less convective rainfall - rain produced as the warm landscape heats up the atmosphere - than the natural savannah forest," said Parlange. "That is hugely concerning, as Burkinabe farmers rely completely on rainfall and groundwater."
For three years, researchers from Canada, Burkina Faso and the United States recorded rainfall, air temperature and humidity, soil temperature and other weather variables at a natural savannah forest in the village of Tambarga in southeastern Burkina Faso, and at a rice and millet field.
According to their study, in 2009 and 2010, when the country received more than 1,000 millimeters of rain per year, the Tambarga savannah forest saw about 15 percent more rainfall than the agricultural site.
Landlocked Burkina Faso has limited water resources. When rain fails, crops die and food shortages follow. In the 1970s, a period of severe drought led to widespread famine that claimed many Burkinabe lives. ■