A Carbon Vault at World's Rooftop
On the eastern edge of the Tibetan Plateau sits the Zoige Basin, which contains the world's largest expanse of high-altitude peatland. At an elevation of 3,400 to 3,900 meters, this vast wetland complex began forming at the start of the Holocene, roughly 11,500 years ago. In the cold, waterlogged conditions, the decomposition of plant matter—primarily sedges and mosses—slowed to a crawl. This process allowed for the gradual accumulation of peat, a dense organic soil.
Over millennia, this slow-motion process created a massive carbon reservoir. The peat in Zoige reaches depths of over 10 meters in some places and stores an estimated 432 to 750 megatonnes of carbon. This immense stock of ancient carbon remained safely locked away, accumulating at an average rate of about 31 to 34 grams of carbon per square meter per year through the Holocene. The entire system regulates of regional hydrology, is a giant sponge that provides up to 45% of the water for the upper reaches of the Yellow River.
An Unstable Stock
Beginning in the 1960s and 1970s, large-scale drainage projects were initiated to convert the marshland into pasture for grazing livestock. Nearly 1,000 artificial channels with a total length of 2,864 km were dug, draining approximately 41% of the total peatland area. This action fundamentally altered the peatland's chemistry. Introducing oxygen into the ancient, water-saturated peat layers triggered rapid decomposition by aerobic microbes.
The consequences are measurable and direct. Carbon that took thousands of years to sequester is now being released as carbon dioxide (CO2) and nitrous oxide (N2O). Studies show that lowering the water table by just 20 centimeters can increase CO2 emissions by 24%. Drained peatlands have shifted from being carbon sinks to significant carbon sources. The process also causes the land to subside as the peat decomposes and compacts, further degrading the ecosystem. This rapid release of ancient carbon contributes directly to regional greenhouse gas concentrations. The Zoige peatlands are also the most important breeding ground for the vulnerable black-necked crane (Grus nigricollis), and the degradation of their habitat poses a serious threat to the species.