Mark Clementz, a professor in the University of Wyoming Department of Geology and Geophysics, announced on Apr. 14 that he and an international team of researchers have published findings showing a link between increased volcanic activity in the Andes during the Late Miocene Epoch and a period of global cooling between 5.4 million and 7 million years ago.
The research highlights how natural processes can influence Earth’s climate over long periods. Understanding these mechanisms is important for anticipating future climate change and its impacts on society.
According to Clementz and his colleagues, volcanic eruptions in the Andes released ash rich in nutrients such as iron into the Southern Ocean. This led to a biological boom, especially among microscopic algae called diatoms, which absorb carbon dioxide from the atmosphere through photosynthesis. The increase in marine life diversity also included significant changes among whales, whose evolutionary shifts during this time are reflected in fossil records.
When whales die, their bodies sink to the ocean floor, storing carbon deep underwater. Additionally, their waste may have contributed to large algal blooms that further increased oceanic carbon storage by causing mass die-offs of other marine life. The combined effect was a reduction of atmospheric carbon dioxide by about 10-15 parts per million according to computer models based on geological data. This drawdown contributed to global cooling within what was otherwise a warmer period known as the Miocene.
Clementz said: “This work improves our understanding of how natural processes can regulate Earth’s climate, which is directly relevant to anticipating future climate change and its impacts on society.” He added that identifying connections between volcanism, ocean productivity, and carbon dioxide drawdown provides insight into factors influencing global climate over long timescales.
The study involved researchers from several universities including Arizona, Buenos Aires, Colorado-Boulder, Birmingham (UK), Lehigh University (US), Bremen (Germany), and Santo Tomás (Chile). Funding was provided by the National Science Foundation.
Clementz hopes this research will inform science-based decision-making related to natural resources and environmental change. He noted it positions Wyoming at the forefront of Earth system science due to its extensive fossil record.
