Mountains play a significant role in the natural regulation of CO2 in the atmosphere. A research team led by Erica Erlanger, Niels Hovius, and Aaron Bufe has conducted a study in the central Italian Apennine Mountains to investigate and balance the competing processes of CO2 uptake and release. The study found that weathering processes in the region lead to an overall CO2 uptake, but in areas with a thin crust and higher heat flow, CO2 outgassing from depths can exceed CO2 uptake through weathering by up to 50 times. The structure and dynamics of the Earth’s crust play a crucial role in controlling the release of CO2 in tectonically active mountain regions.
CO2 plays a vital role in the global carbon cycle, and it is essential to understand the competition between CO2 emission and absorption in mountain landscapes to accurately model climate change. Rocks on the Earth’s surface undergo weathering processes that can absorb or release CO2, depending on the type of rock. Silicate minerals can bind CO2, while the weathering of carbonate and sulphide-containing minerals releases CO2. Additionally, where tectonic plates interact, heating of carbonate rocks in the crust and mantle can lead to chemical reactions that release CO2.
The research team investigated the influence of near-surface and deep-seated processes on CO2 balance in the central Apennines. By analyzing the CO2 content in mountain rivers and springs and estimating CO2 fluxes in different seasons, they found that the region is a net CO2 source. Weathering processes primarily capture CO2, but in areas with a thin crust and high heat flow, CO2 release from depths can exceed CO2 uptake through weathering. This study provides insights into how regional geodynamics impact CO2 release in tectonically active mountain regions.
The research findings have implications for climate models and our understanding of the delicate CO2 balance over geological timescales. By better understanding the processes that control CO2 release and uptake in mountain landscapes, scientists can improve long-term climate models. The study also highlights the importance of considering the role of mountains in the Earth’s carbon cycle and how they have maintained conditions conducive to life by balancing CO2 outgassing and storage processes over geological timescales.
Looking ahead, the researchers suggest that investigating the role of mountains in Earth’s carbon cycle will require a holistic approach. They point to the importance of studying geologically young mountain belts at plate boundaries, where carbonate rocks are likely prevalent both near the surface and at depth. The findings from this study in the central Apennines may have implications for other active tectonic regions around the world. By understanding how CO2 release from depths influences the carbon cycle in mountain landscapes, scientists can gain insights into global processes that impact climate change over time.