2017-06-02 07:47:59

China’s biggest lake getting even bigger is yet another example of global warming affecting the Tibetan Plateau, experts say.

Qinghai Lake has reached its largest surface area since 2001, when satellite remote sensing was first used to measure the lake, according to the latest monitoring data from the Qinghai Institute of Meteorological Science (QIMS), a department of the provincial meteorological bureau.

Qinghai Lake, in northwestern China’s Qinghai province, is expanding due to increased precipitation in the area, said Liu Baokang, the engineer at QIMS in charge of monitoring. He told Sixth Tone that data from the Qinghai Meteorological Bureau shows significantly higher temperatures over the past five decades, as well as more intense and more concentrated rainfall, which increases the water flow into the lake. Melting glaciers were not much of a factor, as there aren’t many near the lake, said Liu.

Using satellite data, QIMS keeps track of the lake’s size using measurements taken in April and September — the dry and wet seasons, respectively. This April, Liu and his colleagues found that the surface area of Qinghai Lake reached 4425.38 square kilometers, an increase of more than 108 square kilometers compared with its average size during dry periods from 2007 to 2016, and nearly the same size as it was September last year, Liu said.

Qinghai Lake started expanding in 2005 after reaching its smallest size on record the year before, Liu said. The lake has now reached the water level it had in the 1970s, state news agency Xinhua reported in March.

Every year Qinghai Lake completely freezes, but last winter was the first time since monitoring started that parts of the lake remained uncovered, China News Service, another state agency, reported in April. The thawing of the lake also started 44 days ahead of time, and by April it was completely unfrozen, it said.

According to Xinhua, Qinghai Lake plays an important role in regulating the regional climate and is a crucial factor in holding back desertification. The expansion of the lake could also impact the livelihoods of local herdsmen, whose grasslands are now flooded, said Lei Yanbin, a researcher from the Institute of Tibetan Plateau Research at the Beijing-based Chinese Academy of Sciences.

Other lakes on the Tibetan Plateau have grown and deepened as well over the past two decades as the area has become warmer and more humid, Lei told Sixth Tone. “The lake expansion may be an indicator of the consequences of climate change,” he said.

The Tibetan Plateau is particularly sensitive to global warming. Researchers discovered earlier this year by examining tree rings that the climate in the sparsely populated area was affected by industrialization as far back as the 1870s. The plateau’s nearly 50,000 glaciers had long been considered remarkably stable despite global warming, but last year saw two major avalanches that scientists believe were the result of increased meltwater.

Editor: Kevin Schoenmakers.

(Header image: An aerial view of the Yarlung Zangbo River in the Tibet Autonomous Region, Sept. 24, 2017. VCG)