Inhabited since 250 B.C., Djenné became a market centre and an important link in the trans-Saharan gold trade. In the 15th and 16th centuries, it was one of the centres for the propagation of Islam.
The great Mosque in the Sahara desert city of Djenné in Mali, West Africa near Timbuktu the largest mud (adobe) building in the world. But the heritage site is under threat due to conditions created by global warming.
The 2,000 traditional earthen houses of the Old Towns of Djenné, an important link in the trans-Saharan gold trade, which sits on the flood plain of the Bani River, were built with the weather in mind.
They sit on hillocks (or toguere) as protection from the region’s seasonal floods. Part of UNESCO’s Old Towns of Djenné World Heritage Site, it is one of Africa’s most revered religious monuments and the largest mud building on earth. The first mosque on the site was built around the 13th century.
However, UNESCO’s report notes the fragility of Djenné and other traditional earthen buildings in the changing climate as they are particularly susceptible to temperature and humidity. The lowest temperature recorded (monthly average) was 22℃ in January 1983 in Djenné. The highest temperature recorded (monthly average) was 36℃ in May 2015 in Djenné. The year 2004 was the warmest in Djenné, the average temperature was: 31℃. 1958 was the coldest year, the average temperature was: 28℃.
Months with the largest precipitation are August, July, September with 660 mm precipitation. Most precipitation occurs in August with an average precipitation 244 mm. The annual amount of precipitation in Djenné is 1548 mm. The average annual temperature is 36℃ in Djenné.
The warmest month of the year is April, with an average temperature: 40℃. Usually January is the coldest month in Djenné, with average temperature 32℃. The difference between the hottest month: April and the coldest month: January is: 8℃. The difference between the highest precipitation (August) and the lowest precipitation (March) is 188mm. While the weather has long affected its structure, the changing climate could be catastrophic.
Traditional custodianship and community engagement of cultural heritage monuments
Every year, the walls of the Great Mosque of Djenné in Mali are rebuilt by the community. During the Crépissage, residents of Djenné, Mali, work together to repair and rebuild the world’s largest mud-brick structure.
The walls of Djenné’s Great Mosque are reconstructed with mud each April in an epic one-day event called the Crépissage (Plastering). The structure requires annual reinforcement as do the town’s traditional adobe homes before Mali’s brief-yet-brutal rainy season, which mostly occurs in July and August, when almost the entire average 1,000mm annual rainfall will descend. This immense undertaking ensures that the mosque will survive the rainy season, despite altering in shape ever so slightly each year.
Once the Crépissage is underway, teams from each neighbourhood in Djenné race to re-plaster the mosque, albeit carefully and precisely. Under the supervision of a guild of 80 senior masons, a highly revered profession in Djenné, young men scramble up the building’s façade carrying wicker baskets dripping with wet clay to smear in thick layers onto the walls, using the toron like ladder rungs. Teams vie with one another to complete their sections first, and winning is a serious matter of pride for competitors, who will also receive a monetary prize of 50,000 West African CFA francs (around £68.50), a significant sum in a town where many earn less than £1 a day.
The entire community contributes to the effort, each group playing a different role. In addition to the actual repair work, men are tasked with preparing the construction material known as banco, a mix of fine clay from the nearby rivers, rice bran, shea butter, baobab powder and water. They rush around furiously, depositing huge amounts of banco into wicker baskets and continuing on to the mosque. Before long the writhing mass of bodies are hard to decipher from the mud itself.
The Crépissage is the one day of the year that women are allowed to enter the mosque, tasked with bringing water from the river to mix with the banco. Children also contribute by carrying baskets of mud to aid the masons, but many simply frolic around and play.
Around five hours after the process began, the morning sun illuminates the newly plastered mosque, which is usually completed by 09:00.
According to Unesco, Djenné is ‘characterised by a remarkable architecture and its urban fabric, of rare harmony’, and the Great Mosque demonstrates thisAccording to Unesco. Yet despite its centuries-long history, the mosque remains a fundamental part of modern society. “The mosque of Djenné is a symbol of social cohesion every year, the communal participation in the maintenance work shows the sense of community and an expression of how to live together,” said Balassiné Yaro, the mayor of Djenné.
The walls of Mali’s Great Mosque of Djenné, rebuilt in 1907, are peppered with toron, protruding bundles of rodier palm sticks. These decorative posts are in fact also permanent scaffolding which are used annually for repairing the mud facade.
The toron’s duality both ornament and expression of repair is a rich seam which can be found elsewhere in wider design history also. Cracks and erosion of the fragile mud structure, caused by rain plus temperature and humidity changes, are repaired.