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Himalayas Emit More CO2 Than They Absorb
8 Sep
Summary
- Himalayan upper Indus basin releases more CO2 than it absorbs.
- Pyrite oxidation releases significant CO2, exceeding silicate weathering.
- Eroding mountain region acts as a net source of greenhouse gas.
New research indicates that the glaciated upper Indus basin in the northwestern Himalayas is a net source of carbon dioxide. Scientists from IISER Pune, Wadia Institute of Himalayan Geology, and IIT Roorkee found that the "rusting" of pyrite, commonly known as "fool's gold," releases substantially more CO2 than is absorbed by the weathering of silicate rocks in the region.
This process challenges the prevailing understanding that Himalayan chemical weathering primarily serves as a natural sink for atmospheric CO2. The study, which analyzed water samples from the Indus headwaters, found that approximately 68% of the sulfate is linked to pyrite oxidation. This oxidation releases about 4.4 × 10⁵ moles of CO2 per square km annually, while silicate weathering uptakes only about 1.4 × 10⁵ units.
Researchers attribute the high rates of pyrite oxidation to the area's geology, rapid erosion, and extensive glacial cover, which continually expose fresh rock surfaces. Interestingly, the study also observed that this CO2-releasing effect diminishes as the Indus River flows towards the plains, with lower floodplain regions showing a net CO2 uptake. This highlights glacier-fed mountain rivers as significant geological sources of CO2.
