GREEN

China's Largest Freshwater Lake Is Shrinking

And activists say the plan to save it could make things much worse.

04/01/2017 7:48 AM AEDT | Updated 04/01/2017 7:54 PM AEDT
VCG/VCG via Getty Images
Half a million migratory birds, including the critically endangered Siberian crane, are said to flock to China's Poyang Lake every year.

China’s largest freshwater lake is under serious threat, and it seems no one can agree on how to save it. 

Poyang Lake can swell to over 1,700 square miles, an area larger than Rhode Island. But photographs released by China’s state-run Xinhua News Agency in November show it completely dry in parts, desiccated by drought.

The website EcoWatch describes tourists walking “on large portions” of the parched lake, located in Jiangxi province. Photos show ships stranded on the exposed lakebed, while cattle graze on what is usually the lake floor. 

Poyang is connected to the Yangtze River and is home to several critically endangered species, including the Yangtze finless porpoise.

The lake has been shrinking for years. Since 2003, Poyang’s dry period has been starting earlier and lasting longer, according to a 2015 study by researchers at the East China Normal University in Shanghai. This year, the dry season began more than 50 days earlier than usual.

Climate change, industrial activities like sand mining and the construction of the enormous Three Gorges Dam, which opened in 2003 and spans the Yangtze Riverare all possible culprits for the lake’s decline.

Local authorities are now scrambling to save Poyang. But not everyone is thrilled with their plan.

In 2008, the Jiangxi provincial government first proposed building a 10,000-foot sluice gate ― in effect, a dam that would be constructed across the channel that links Poyang to the Yangtze ― to keep more water in the lake during the dry season. According to a report published by local officials last month, the gate could help raise water levels, improve water quality and promote shipping on the lake, among other benefits.

China’s Ministry of Environmental Protection recently began an environmental risk assessment of the plan, The New York Times reported last week. If senior officials do not reject the proposal for the gate, construction should start once the review is concluded.

Environmentalists, however, are rushing to put the brakes on the project, saying the gate could trigger “irreversible” ecological damage.

“I think [they’re] proposing a solution without understanding the causes of the problem,” David Shankman, a professor at the University of Alabama who has studied Poyang Lake, told the Times. “The whole idea of the dam is that there would be some economic benefit, but there may be potential long-term ecological problems.”

For one, further cutting off Poyang’s connection with the Yangtze could cause drought conditions to worsen. 

“Rivers and lakes depend on each other,” environmental activist Wang Yongchen told Guangzhou Daily in 2012. “The Three Gorges Dam has already kept water from the Yangtze and the lake, and the new Poyang Lake dam would further obstruct the natural connection.”

Scientists say the project could also “irreparably” change the lake’s seasonal flood pulse and cause abnormally high water levels during the dry season. This could submerge the lake’s wetlands, which provide a critical habitat for birds. 

Half a million migratory birds flock to Poyang Lake every year, including the critically endangered Siberian crane. About 3,000 of the birds remain on Earth, according to the International Crane Foundation.

“The problem [with the dam] is not whether the Siberian cranes are coming to Poyang for the winter, the question is whether Siberian cranes will still exist in this world,” Zhou Haixiang, a researcher on migrating birds at the Shenyang University of Technology, told the South China Morning Post last month. “We have no other choice but to protect them.”

Nir Elias/Reuters
Dead fish on the banks of drought-affected Poyang Lake in 2008. One lifelong fisherman told The Guardian in 2012 that he had not been out on the lake in over a year and had never seen it so dry.
VCG via Getty Images
Cattle graze on what is usually the floor of Poyang Lake in May 2011. China's largest freshwater lake has been experiencing a "dramatic and prolonged" recession, according to a 2015 study by researchers at the East China Normal University in Shanghai.
REUTERS/Stringer
A rescue worker measures a recovered finless porpoise before releasing it back to the wild in Poyang Lake on March 26, 2015. Oceanography and fisheries experts said the finless porpoise is endangered due to pollution and water shortages, among other threats.

The dam also threatens other endangered species that rely on the lake, activists say. Among them is the Yangtze finless porpoise, which lives exclusively in the Yangtze River and the two lakes connected to it, Poyang and Dongting.

The rare porpoises have experienced a population decline of over 13 percent per year, and could become extinct in the next five to 10 years, the World Wildlife Fund said last year. Just 1,000 are left in the wild, according to the WWF.

The WWF has opposed plans for the sluice gate, saying that it could “irreversibly and unpredictably” impact water quality and biodiversity. A “dam-free project” would be the “best option for Poyang Lake to sustain a healthy ecological system,” the group said in 2014.

Instead of building the sluice gate, some scientists have proposed halting sand mining to save Poyang. The lake bottom is reportedly the world’s largest sand mine

A 2014 study by researchers from Chinese, American and French institutions estimated that 236 million cubic meters of sand is removed from the lake every year, largely to make concrete for construction projects. That’s about 30 times more than the amount of sand that flows in annually from tributary rivers. 

“I couldn’t believe it when we did the calculations,” the University of Alabama’s Shankman, who was one of the study’s authors, told the Pulitzer Center earlier this year of the findings.

Lakepedia published a before and after image of Poyang lake on its blog to illustrate the extent of the water body’s decline. The “before” image was captured on October 9th, 2000, while the “after” image is from September 27th, 2016. Use the slider to compare the two images. The story continues below.

Russia’s Lake Baikal, the world’s deepest lake, and America’s Great Lakes are also suffering from threats that include rising temperatures, low water levels and nearby forest fires.

According to a 2015 study funded partly by NASA and the National Science Foundation, the world’s lakes are warming faster than the oceans and atmosphere. 

“The message we’re getting from our lakes is that they’re getting more and more stressed,” Catherine O’Reilly, the global study’s lead author, told The Associated Press. “With these rates of warming, the problems we’re seeing will become increasingly common.”

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