The uplift of East Africa during the Miocene epoch dramatically transformed the region’s climate and ecosystems, promoting the expansion of grassland and reshaping habitats for mammals and early hominoids. This is revealed in a new study published in Science Advances by researchers at Stockholm University, ETH Zurich, and the Swedish Museum of Natural History.

”Our results show that tectonic uplift, combined with declining CO₂ during the Middle Miocene Climate Transition, substantially reduced forest cover and promoted grassland expansion across East and Central Africa,” says Niklas Werner, now a doctoral researcher at the Department of Earth and Planetary Sciences, ETH Zurich. He conducted this research during his master’s thesis project at Stockholm University in 2022–2023.

The researchers used the high-resolution Earth System Model EC-Earth3, coupled with a dynamic vegetation model, to simulate climate and vegetation responses to East African uplift across three key Miocene intervals (25, 20, and 15 Myr) under varying atmospheric CO₂ levels.

”These environmental transformations likely facilitated faunal dispersals and evolutionary turnover, especially among large herbivores and early crown hominoids,” says Lars Werdelin, professor at the Swedish Museum of Natural History.

“This work demonstrates the value of combining geodynamic modeling, climate simulations, and paleontological data to uncover how tectonics shaped ecosystems,” adds Qiong Zhang, Professor at the Department of Physical Geography, Stockholm University, who initiated and led this research project.

Early efforts to simulate uplift effects began in 2018 as part of a Bolin Centre integration project, using idealized elevation data. But due to limitations in topographic reconstructions, initial simulations were inconclusive.

”The breakthrough came in 2022, when Niklas Werner took on this topic for his Master’s thesis at Stockholm University, supported by improved model capabilities and better paleotopographic data,” says Professor Qiong Zhang.

About the study:
This research stems from a long-term collaboration initiated by Professor Qiong Zhang at Stockholm University. It integrates high-resolution climate modelling with paleographic and fossil data to explore the co-evolution of landscape and fauna in East Africa. Niklas Werner, now a doctoral researcher at Department of Earth and Planetary Sciences, ETH Zurich, conducted the core analysis and visualizations, and led the manuscript writing. Professor Lars Werdelin, Swedish Museum of Natural History, provided expertise on fossil evidence and Miocene faunal transitions, and Dr. Zhengqian Wang, Department of Physical Geography, Stockholm University, contributed to configuring the EC-Earth model experiments.

The project was originated from a Bolin Centre Integration Project in 2017 and received further support from the Swedish Research Council (VR).