China's Solar Boom Is Squeezing Out Birds, International Study Finds

China's rapid expansion of solar power is reducing local bird diversity, particularly in wealthier and non-desert regions, according to a study led by researchers at Nanjing University of Information Science and Technology with colleagues from China, Vietnam and the United States. Published in the journal Science, the study found that solar expansion has eaten into birds' foraging and breeding grounds and left remaining habitat more fragmented, setting China's carbon-reduction policies against biodiversity conservation in some areas.

China's solar farm footprint reached an estimated 4,520 square kilometers in 2024, part of a carbon-neutrality strategy aiming for solar to make up nearly 45% of the country's energy mix by 2060. Using data on solar policy stringency and bird observations across more than 2,300 county-level divisions from 2014 to 2023, the researchers measured bird diversity with the Shannon Index, a common tool that accounts for both the number of species present and how evenly their populations are balanced.

The study found a negative relationship between the strength of solar policy support and bird diversity: every one standard deviation increase in policy support was linked to a 2.1% reduction in diversity. The decline was more pronounced in wealthier, ecologically complex areas, while in China's arid Three-North region — where solar irradiance is high but vegetation is naturally sparse — the effect was not significant. Both resident and migratory birds were affected, particularly where aggressive solar policies overlapped with migration corridors.

The researchers also identified a pattern they called "inferior greening," in which an increase in leaf area around solar installations did not necessarily translate into better wildlife habitat. "Our findings highlight a critical green dilemma: without meticulous spatial planning, policy-driven solar expansion can inadvertently compromise local biodiversity," the team wrote, calling for future solar development to include biodiversity safeguards, especially in economically developed regions with complex habitats.