Researchers studying the Southern Andes report that continental volcanic arcs significantly contribute to the global carbon cycle by removing CO2 through silicate weathering. After sampling 22 rivers and 16 hot springs, they estimate the Southern Andes sequester about 1% of atmospheric CO2 each year. The team warns that climate change — via stronger storms in some places and prolonged droughts in others — could alter weathering rates and weaken this natural carbon sink. They call for more research on other volcanic arcs to better assess global impacts.
Volcanic Mountain Ranges Lock Up Carbon — Climate Change Could Undermine This Natural Sink
Researchers studying the Southern Andes report that continental volcanic arcs significantly contribute to the global carbon cycle by removing CO2 through silicate weathering. After sampling 22 rivers and 16 hot springs, they estimate the Southern Andes sequester about 1% of atmospheric CO2 each year. The team warns that climate change — via stronger storms in some places and prolonged droughts in others — could alter weathering rates and weaken this natural carbon sink. They call for more research on other volcanic arcs to better assess global impacts.
11:12 AM, 11/11/2025Environment
Volcanic mountain chains play a surprising role in the global carbon cycle
New research from the Southern Andes suggests that large continental volcanic arcs help remove carbon dioxide from the atmosphere through chemical weathering of silicate rocks. The study — published in Earth and Planetary Science Letters and led by Amanda Peña-Echeverría of the University of Chile — sampled 22 rivers and 16 hot springs in a region that contains more than 200 hot springs and abundant rainfall.
The authors found that reactions between water, volcanic gases and fresh silicate rock at both high and low temperatures enhance the transport of dissolved materials to the ocean and lead to long-term CO2 consumption. Based on their measurements, the Southern Andes sequester roughly 1% of atmospheric CO2 each year via silicate weathering.
How volcanic weathering works
Volcanic arcs are especially effective at chemical weathering because high elevations expose fresh rock and volcanic resurfacing continually supplies new material for breakdown. In active volcanic areas, high-temperature fluids and gases from depth can alter river chemistry and accelerate weathering reactions that ultimately convert atmospheric CO2 into dissolved inorganic carbon carried to the ocean.
Climate change could change the balance
However, the researchers warn that climate change may substantially modify weathering rates in continental volcanic arcs. Warming can increase extreme precipitation and stronger storms in some regions, potentially accelerating weathering rates, while prolonged droughts in other areas could sharply reduce chemical weathering and a volcanic arc's ability to absorb carbon.
"Our results highlight the significance of exploring interactions between low- and high-temperature weathering in volcanic regions to improve our understanding of silicate weathering and carbon balance in the global cycles," the study noted.
Although the Southern Andes appear to account for nearly 1% of global carbon consumption from chemical weathering, the team calls for broader studies of other volcanic arcs to determine their combined contribution to the global carbon budget. Understanding how natural carbon sinks will respond to changing climate and human-driven emissions is crucial for accurate carbon accounting and long-term climate projections.
Policy and research implications
The findings underscore the need for continued monitoring and expanded research on volcanic arc weathering worldwide. They also reinforce the value of policies that reduce greenhouse gas emissions and strengthen natural carbon sinks, while reminding policymakers that changes in climate can feedback on the Earth system in complex ways.