A weather record kept in the National Institute for Agronomic Studies and Research in the Democratic Republic of the Congo. Derrick Muheki
The Congo Basin is one of the few places on Earth where the Intergovernmental Panel on Climate Change has failed to track the long-term shift in extreme heat and rainfall. The reason is a lack of readily available data. To fill this gap, scientists have digitized thousands of handwritten weather records, which reveal the impact of warming in the region.
The records, recovered from archives in Belgium and the Democratic Republic of the Congo, span the years 1908 to 2023. To digitize the data, scientists had to scan more than 9,000 pages that together included more than a million observations.
“Seeing how fragile these paper archives were as I was visiting [the archive in the Democratic Republic of the Congo] made me realize how urgent this data rescue work is,” said Derrick Muheki, a PhD candidate at Vrije Universiteit Brussel. “Just months before my visit, part of the archive had been damaged by fire. We could have lost decades of irreplaceable data.”
The digitized data revealed a clear warming trend in the latter half of the 20th century. Between 1961 and 1990, scientists found, the average daily temperature in the Congo Basin rose by about 0.9 degrees F, while the average number of hot days per year nearly doubled. As the Congo warmed, scientists found, it also saw more extreme heat and more heavy rainfall. Their findings were published in Earth System Dynamics.
The trends observed in the Congo mirror changes seen in Europe, North America, and elsewhere. But unlike those regions, the Congo lacked the climate data needed to study changes over the long term.
Now, combining the newly digitized records with other, previously rescued data, scientists have assembled one of the largest climate datasets for the Congo Basin. The data not only offers a fuller picture of weather history but could be used to improve projections of future climate change, scientists say.
“Our work further highlights the urgent need for more data rescue projects, especially in data-sparse regions, to close knowledge gaps on climate trends,” said Wim Thiery, a professor at Vrije Universiteit Brussel, who was involved in the new research. “This is particularly important for regions in the Global South that are severely impacted by climate change already today.”
The lack of weather data is an ongoing problem, scientists say. In Africa, a scarcity of weather stations is making it harder to warn people about upcoming extreme weather events or to determine the role of climate change after the fact.