Himalayan Rocks Release More CO2 Than Thought

A recent study focusing on the upper Indus basin in the northwestern Himalayas has uncovered a surprising geological source of atmospheric carbon dioxide: the oxidation of pyrite, also known as "fool's gold." Conducted by researchers from the Indian Institute of Science Education and Research (IISER) Pune, the findings were published in the journal Chemical Geology on July 17, 2026. The research indicates that in glaciated areas of the upper Indus basin, the release of CO2 from pyrite oxidation can surpass the amount consumed by silicate rock weathering. This implies that certain rapidly eroding, glacier-fed Himalayan landscapes might act as net geological sources of CO2, rather than carbon sinks, altering the established view of mountain weathering's influence on the long-term carbon cycle.

This phenomenon is significant as the Himalayas represent one of Earth's fastest-eroding mountain systems. Continuous exposure of fresh rock surfaces by glaciers and rivers accelerates chemical reactions. While silicate weathering is generally recognized for consuming atmospheric CO2 over geological timescales, the presence and subsequent oxidation of minerals like pyrite introduce a complexity to the Earth's carbon balance. The study analyzed water chemistry and isotopes to quantify this process, confirming a net geological release of CO2 from these specific Himalayan landscapes. Researchers emphasize this is a long-term geological process, not indicative of a significant modern-day CO2 source comparable to human emissions, but crucial for understanding Earth's climate regulation over millions of years.