Do South China Sea waste claims pass the smell test?
- A US firm claims that Chinese ships moored at a disputed reef were dumping tonnes of human waste into the waters and killing coral reefs
- But some scientists say there is no scientific evidence to support the allegations, which are based on an analysis of satellite images
However, some have questioned the accuracy of the analysis by the US AI software company Simularity, which was based on satellite imagery and is not peer-reviewed.
Simularity ran around 100 satellite images taken from the European Space Agency through AI-driven geospatial analysis software and concluded that the images showed how algal blooms that can be deadly for coral reefs had grown around the areas where Chinese vessels had been mooring since 2016.
The report concluded that this was most likely due to human waste being dumped into the surrounding waters.
David Baker, an associate professor from the school of biological sciences at the University of Hong Kong, said dumping human sewage was not a big concern in an open ocean like the South China Sea as the waves underneath the boat would dilute and disperse the waste until it was no longer harmful.
“I wouldn’t be surprised to hear that any fishing vessel in the open ocean is discharging waste. I don’t think that is an unusual practice,” Baker said.
“I think the general consensus is that, for small numbers of people in a vast open sea, the impact of human waste is going to be minimal.”
He said the report did help to shine a light to the global problem of overfishing and sea pollution, but said its conclusions were not “based on any scientific evidence”.
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Though satellite images can monitor algae blooms by tracking chlorophyll-A – a bacterial pigment that shows up as white patches in multispectral imaging – this could not be used to show the degradation of coral reefs was caused by pollution discharged from the vessels, Baker said.
Simularity’s chief executive Liz Derr said that while there was nothing unusual about vessels discharging waste in the open ocean, this had to be done while the vessel was moving and in an area with enough wave action to dilute the waste nutrients.
“The problem is [the Chinese vessels] are sitting in the middle of an atoll, there are 200 and some ships,” she said. “They’re in an atoll where there is not a lot of wave action and remember this is the place ships went to hide from the storms, it’s fairly secure.”
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An atoll is a ring-shaped coral reef that partially or completely encircles a lagoon. Derr estimated that the fleet parked on the Union Banks had dumped around a tonne a day of human waste.
She said the problem was compounded by the fact that these vessels were practically stationary for long periods of time, making it easier for the human waste to concentrate in a small area, which then allows for algae blooms to flourish.
“It’s well known that discharging waste while a ship is anchored is inappropriate,” Derr said.
Under Chinese law, ships more than three nautical miles (5.5km) away from the nearest land mass must be moving at a speed of at least four knots (7.4km/h) before they are allowed to discharge sewage.
“We know the ships are stationary for long periods of time, they tie them all up together, we see these chains from two to 18 ships, all tied up and anchored together, which is really distinctive and we saw that at Whitsun Reef,” Derr said.
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Derr acknowledged that analysing satellite images had its limitations, adding she was hopeful that either marine biologists or the Philippine coastguard could go to the Union Banks and measure the water quality, as well as confirm the boats there were indeed all Chinese vessels.
However, she also said the report’s methodology was not unusual, pointing to space agencies as an example. “Measuring chlorophyll blooms from space is a well understood, totally legitimate method. They have designed satellites for this purpose,” she said.
Derr said she was working on a report that showed how other reefs near the Union Banks that were not exposed to significant human activity did not see comparable increases in chlorophyll concentration.
Chinese media outlets have sought to discredit the report after the Philippine Defence Secretary Delfin Lorenzana questioned its accuracy – citing its use of a picture of a ship dumping waste near the Great Barrier Reef in 2014 on the cover.
The nationalist tabloid Global Times said Lorenzana’s comments were a “slap in the face” for the report.
Derr said that the image was only a cover photo, and had nothing to do with its findings. The photo was included to add a more visual element to the report, because “ship waste dumping from 10m satellite images is hard for people to appreciate as it just looks like a few grey to white pixels”, she said.
The image’s location and provenance was described as “unknown” in the report, and it was taken from news outlet The Maritime Executive.
“We never stated that this ship was from the Spratlys, or was Chinese,” Derr said. “I regret including that picture because it has given people an excuse to disregard our findings outright, without even looking at the actual report and the scientific approach taken to derive the findings.”
Despite Beijing’s condemnation of Simularity’s report, there are signs the findings struck a chord.
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A meeting held on July 15 by the municipal government of Sansha – a body established by China to administer a group of 260 islands, reefs and beaches located in the disputed Spratly and Paracel Islands and Macclesfield Bank – demanded that “the fragility and irreversibility of islands and reefs should be fully recognised”.
All related departments were asked to “fight together the battle of pollution prevention and control, and safeguard the clear sea and blue sky of Sansha”.
