NewRoFoundation

Minerals in the mud from the Zambezi River basin tell Sarah Athir that back before the recording of human history began, southeast Africa saw precipitation in patterns similar to the ones that are leading to severe flooding and drought now.

She determined the precipitation by peering at the dried-out mud samples through a microscope and tweezing out minerals such as muscovite that wash off rocks into the mud during erosion. The deepest sample came from 16 meters down, dating back 11,500 years.

Muscovite grains then went through radiometric dating.

“After this, the muscovite grains were sent through a mass spectrometer which calculated the ages of each of the grains,” she said.

The results show a shift underway in the Inter-Tropical Convergence Zone (ITCZ), a low-pressure rain belt near the equator. They also indicate that a similar shift occurred eleven and a half millennia ago.

The ITCZ’s southward movement presages severe flooding south of the Zambezi, and severe drought to the north. The finding jibes with changes underway such as the expansion of dessert in the Sahel region at the south edge of the Sahara.

“With this information, communities in the south can begin to prepare for the devastating effects that storms and floods induced by the ITCZ can have on their infrastructure, food security, health and economy,” she said. “Communities relatively north can begin to prepare for the effects of droughts.”

Long interested in climate change, Athir chose the Zambezi River project because Africa is particularly susceptible to its impacts. In the end, she learned more than she’d expected. Of the project’s success, she said; “It’s promising, it’s exciting and it’s inspiring because I feel like I could do more with this and continue to improve my results.”