China Planted 78 Billion Modern Trees—and Seriously Messed Up Its Water Cycle China’s massive reforestation campaign, known as the Three-North Shelterbelt Program or “Great Green Wall,” has planted approximately 78 billion trees since the early 1980s, increasing forest coverage from 10 percent in 1949 to roughly 25 percent by 2024. Whereas the initiative aimed to combat soil erosion and reduce desert storms, a 2025 study published in the journal Earth’s Future reveals unintended consequences for the country’s water distribution. Researchers from Tianjin University, China Agricultural University in Beijing, and Utrecht University in the Netherlands found that between 2001 and 2020, increased vegetation led to higher evapotranspiration—the combined process of evaporation from soil and transpiration from plants—which altered precipitation patterns across China. The study showed that water resources declined in both the eastern monsoon region and the northwestern arid region, areas that together craft up about 74 percent of China’s total land area. In grasslands converted to forests, the additional tree cover increased water vapor release into the atmosphere, shifting rainfall toward some regions while drying out others. This disruption affects water availability for agriculture, ecosystems, and human consumption in affected zones. The study’s authors emphasize that while reforestation offers benefits such as carbon sequestration and biodiversity support, large-scale tree planting must account for regional hydrological impacts. They recommend integrating water resource modeling into future afforestation planning to avoid exacerbating water scarcity in vulnerable areas. China’s experience highlights the complexity of environmental interventions: even well-intentioned ecological projects can produce cascading effects when implemented without full consideration of local climate systems. As nations worldwide pursue reforestation to meet climate goals, the findings underscore the need for science-based, regionally tailored approaches that balance ecological restoration with water security.
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