Science Study Linking China's Solar Boom to Bird Decline Faces Data Scrutiny

A study published in the leading US journal Science, which concluded that China's policy-driven expansion of solar energy has harmed bird diversity, has come under scrutiny after allegations that its analysis relied on an implausible data point: a single logged observation of 2.1 billion little egrets in one wetland park, more than the entire global population of the species. The study, by researchers in China, Vietnam and the United States, was published on August 20 and compared the strength of China's solar policy against changes in bird diversity from 2014 to 2023.

The bird-count data came from the China Birdwatching Record Centre, the country's largest citizen-science platform for bird observations. In late August, the China Ornithological Society said potential errors in the centre's records may have influenced the study's conclusions, pointing to the 2015 egret count and a separate 2022 observation of 1.3 billion red-billed blue magpies, both logged in Guangdong province. A 2023 Wetlands International estimate placed the entire global little egret population at up to about 3 million.

The society said a table in the Science paper showed bird counts for some subcategories, such as total resident birds, exceeding 3 billion, and that the paper "provides no information on birdwatching data quality control, making it impossible to accurately assess the reasonableness of the data used." It argued the study's methodology and its use of a specific bird diversity index were also flawed.

Science's communications director, Meagan Phelan, said on August 27 that the concerns had reached the journal and that it was evaluating them. A Lund University researcher in Sweden said in scholarly commentary that the study's design showed the effects of local solar policies but did not prove solar development directly caused the bird changes, while researchers in mainland China and Hong Kong said the finding needed further evaluation before shaping policy.

The paper concluded that without careful spatial planning, solar expansion can compromise bird diversity through the loss of breeding and foraging grounds, and argued that future development needs stricter safeguards, particularly in non-desert, more developed regions where it found bird diversity loss was more pronounced.