During the last two decades, China has pursued a policy of massive reforestation that transformed its landscape and, according to a study published in Earth’s Future in 2025, also modified the water cycle.
Between 2001 and 2020, the country promoted programs like Grain for Green and the protection of natural forests, especially on the Loess Plateau, with the aim of curbing desertification and restoring degraded ecosystems.
The strategy began in 1978 with the Great Green Wall, designed to halt the expansion of arid zones in the north. In 50 years, forest coverage increased from 10% to 25% of the territory, an area equivalent to that of Algeria. These efforts represent 25% of the global increase in forest area since the year 2000.
The phenomenon of evapotranspiration
The massive planting of trees altered the water circulation throughout the country. The key mechanism is evapotranspiration, a process by which water evaporates from the soil and is released into the atmosphere through plant transpiration.
- Trees, with deep roots, absorb water even during droughts.
- This activates the water cycle, redistributing water resources between regions.
- However, the “water cost” is high: evapotranspiration increased faster than precipitation, causing local water losses.
Unequal water redistribution
The study reveals that reforestation has generated a displacement of water resources:
- Decrease in freshwater in eastern China (monsoon area) and in the arid northwest.
- Increase in freshwater on the Tibetan Plateau.
This means that although the water cycle is more active, some regions lose water while others gain it.
Social and environmental implications
The paradox is especially relevant because northern China concentrates 46% of the population and 60% of the arable land, but only has 20% of the water resources.
Reforestation, although positive for combating desertification and climate change, must be managed locally to avoid imbalances.
A nuanced restoration model
The Chinese case demonstrates that reforestation policies can have unexpected effects:
- Benefits: increase in forest coverage, ecosystem recovery, and reduction of desertification.
- Challenges: unequal water redistribution, pressure on agricultural regions, and need for territorial planning.
China’s experience shows that planting trees can change not only the landscape but also the hydrological cycle of an entire country. Massive reforestation is a powerful tool against climate change, but it requires careful management to balance environmental benefits with social and economic needs.
