Rapid Himalayan Erosion Triggers Hidden Source Of CO2: Study, Pg13

Key Highlights:

• A recent study indicates that rapid erosion in the Himalayas, particularly due to glacier activity, acts as a significant geological source of carbon dioxide (CO2).
• This CO2 release, primarily from pyrite oxidation, may counteract the cooling effect traditionally associated with silicate weathering.
• Researchers from IISER Pune, Wadia Institute of Himalayan Geology, and IIT-Roorkee published these findings in Chemical Geology.
• The study, focused on the upper Indus basin, estimated CO2 oxidation rates to be three times higher than CO2 uptake by silicate weathering.
• Recent flash floods in Nepal underscore the destabilization of Himalayan glaciers, which contribute to the intensified erosion process.

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Detailed Insights:

• The ongoing collision of the Indian plate with the Eurasian plate drives Himalayan uplift and erosion, exposing diverse minerals.
• Silicate minerals typically react with atmospheric CO2, sequestering carbon into seafloor sediments, a process historically linked to Earth's cooling.
• However, rapid erosion exposes pyrites (also known as fool's gold), whose sulphides oxidize into sulphuric acid upon contact with air and water.
• This sulphuric acid subsequently reacts with carbonate rocks, leading to the release of CO2 into the atmosphere.
• The research utilized the ratio of sulphur and oxygen isotopes in the Indus river system to distinguish between different sulphate origins.
• The study found that while flatter floodplains downstream function as CO2 sinks, the steep mountainous regions are net CO2 sources.
• Glaciers intensify this process by efficiently crushing rocks and exposing pyrites, making erosion a "double-edged sword" for the carbon cycle.
• These findings suggest a long-term impact on the global carbon cycle and a potential contribution to climate warming over geological timescales.

Scientific/Technical Concepts Involved:

• Silicate Weathering: A natural geological process where silicate minerals react with atmospheric CO2, removing it from the atmosphere.
• Pyrite Oxidation: A chemical reaction where sulphide minerals like pyrite react with oxygen and water, producing sulphuric acid and releasing CO2 when reacting with carbonates.
• Carbon Cycle: The natural biogeochemical cycle involving the exchange of carbon among Earth's atmosphere, oceans, soil, and living things.
• Isotopes: Atoms of the same element with differing numbers of neutrons, used as tracers in scientific studies to identify origins or processes.