China lakes become more green and greener due to climate change

China lakes become more green and greener due to climate change

This undated photo depicts a bird's-eye view of the Zhuonai Lake in Qinghai province. BEIJING - Chinese scientists and international experts have recently discovered that China's lakes have become more bluer and greener because of factors that include higher temperatures and rainfall.

In lake water, volatile substances can interact with sunlight, such as light absorption and scattered scattering, resulting in different colors. previous studies have mapped the differences in lake colors in China but their changing patterns and relevant reasons remain unresolved over the past few decades.

Scientists from China under the Chinese Academy of Sciences and other institutions in China, as well as those from the U.S. and Estonia, used satellite images to track annual trends of colors of more than 2,500 lakes in China since the 1980s.

The study published recently in the journal Geophysical Research Letters found the colors for 68 percent of the lakes from 1984 to 2021 shifted toward shorter visual wavelengths. In Western China, blue lakes, such as the Qinghai-Tibet Plateau, became bluer, while green-yellow lakes in eastern China shifted to greener colors.

The authors also revealed the reasons behind such color changes. The Qinghai-Tibet Plateau's lakes are deep, with their water colors mainly blue. The increase in transparency and polarization caused by climate warming and humidification have led to their colors turning bluer in the past 40 years.

In eastern China, the lakes are mostly shallow and their colors are green or yellow. The decreasing wind speed in most areas in the past 40 years has weakened the sediment resuspension, while the increase of vegetation in the basin reduces the particulate matter entering the lake. Both of them have made the lakes greener.

The study has been carried out to understand the changes in lake colors and their response to climate change and human activities, the researchers said.