A vast tree-planting campaign around the Taklamakan Desert in northwest China has transformed parts of the once-barren landscape into a seasonal carbon sink, according to new research published in Proceedings of the National Academy of Sciences (PNAS).
The Taklamakan, spread across roughly 337,000 square kilometres in China’s Xinjiang region, has long been considered one of the world’s most inhospitable deserts. Ringed by high mountain ranges that block moist air, it receives minimal rainfall often less than 16 millimetres per month even during the wet season.
But satellite observations and ground measurements now indicate that the desert’s vegetated fringes are absorbing more carbon dioxide (CO₂) than they release during the summer months. In climate terms, that means the area has shifted from being a carbon source to a carbon sink.
The shift is largely attributed to China’s massive afforestation drive, widely known as the Three-North Shelter Forest Program, or the “Great Green Wall.” Launched in 1978, the programme aims to curb desert expansion and reduce sandstorms by planting trees and shrubs across northern China.
According to official figures, more than 66 billion trees have been planted nationwide since the project began. Around the Taklamakan, a shelterbelt stretching approximately 3,000 kilometres was effectively completed in 2024, forming a green ring around parts of the desert’s shifting dunes.
Researchers led by Yuk L. Yung of NASA’s Jet Propulsion Laboratory and the California Institute of Technology analysed 25 years of satellite data tracking vegetation cover and photosynthesis. They found that average CO₂ concentrations near the green belt dropped by around three parts per million during the wet season a modest but scientifically meaningful decline over such a large area.
Vegetation indices derived from satellite imagery also show a steady rise in plant growth and photosynthetic activity, suggesting that more carbon is being stored in biomass and soils.
Local climate effects emerging
The study further reports that summer rainfall in vegetated zones has roughly doubled compared with levels observed decades ago. As trees and shrubs release water vapour through transpiration, they increase atmospheric moisture, potentially encouraging cloud formation and additional rainfall. This creates a feedback loop in which more vegetation supports more moisture, which in turn helps sustain plant growth.
However, scientists caution that this does not mean the desert is turning into a forest. The greening is concentrated along its margins and remains dependent on water availability.
Environmental trade offs under scrutiny
While the findings highlight the potential of large-scale ecological engineering, they also raise concerns. In an already water-scarce region, maintaining millions of trees requires significant groundwater and irrigation resources. Hydrologists warn that excessive planting could strain aquifers and compete with agricultural and domestic water needs.
Ecologists have also questioned the heavy reliance on hardy, fast-growing species such as poplars and saxaul. Monoculture plantations can be more vulnerable to pests, disease and prolonged drought, potentially undermining long-term carbon storage.
Even the programme’s impact on sandstorms remains debated. Although tree belts can slow winds and trap sand locally, broader dust storm trends are influenced by regional meteorology and land-use changes beyond planted areas.
A model for other drylands?
Despite the caveats, the Taklamakan project is being closely watched by policymakers in other arid regions. It demonstrates that, under certain conditions, drylands can enhance carbon storage through deliberate human intervention.
Researchers stress, however, that success depends on careful species selection, realistic water management and long-term ecological monitoring not just the number of trees planted.
For now, the greening of the Taklamakan stands as one of the world’s most ambitious attempts to reshape a desert landscape and a reminder that climate solutions, even when effective, come with complex trade-offs.