China is hardly unique. The number of environmental laws on the books worldwide has increased 38-fold since 1972, according to an exhaustive UN environment report released on Thursday. But the political will and capacity to enforce those laws often lags, undermining global efforts to curb issues like wildlife trafficking, air pollution and climate change, the report found.

“The law does not self-execute,” said Carl Bruch, a study co-author and director of international programmes at the Environmental Law Institute in Washington.

Each of the 33 pangolins transferred to the care of a government-run wildlife rescue centre in China’s Guangxi province died within three months, according to records obtained by the non-profit China Biodiversity Conservation and Green Development Foundation and shown to Associated Press.

What is still unclear is what happened to their bodies.

Pangolins are insect-eating, scaly mammals, playfully described by the International Union for Conservation of Nature as “resembling an artichoke with legs and a tail”.

Their scales – made of keratin, the same material in human finger nails – are in high demand for Chinese traditional medicine, to purportedly cure arthritis and boost male virility, although there is no scientific backing for these beliefs.

The price of pangolin scales in China has risen from US$11 per kilogram (2.2 pounds) in the 1990s to US$470 in 2014, according to researchers at Beijing Forestry University.

Scientists have designated all eight species of pangolins as being at risk of extinction – four species in Asia and four in Africa. More than 1 million pangolins were trafficked between 2004 and 2014, for their scales, meat and blood, with China and Vietnam the largest markets. In the last two decades, the number of pangolins worldwide has dropped by about 90 per cent.

In 2016, the Convention on International Trade in Endangered Species of Wild Fauna and Flora adopted a worldwide ban on commercial trade in pangolins, and China later approved that ban. Pangolins are also listed as a protected species in China. Although Chinese state-run media have publicised a few high-profile poacher busts, watchdogs say a thriving black market for endangered-animal parts persists.

In November 2017, customs officials in Shenzhen in southern China seized 13.1 tons (11.9 metric tonnes) of pangolin scales – reportedly the largest-ever seizure of scales from Africa – according to state media.

The penalties offenders face are not always publicised, but in another case involving a smaller shipment of scales, two smugglers received prison sentences of five years, state media said.

“It’s significant that China has adopted laws against trade in many endangered species, but the law itself isn’t enough to protect a species from extinction,” said Jinfeng Zhou, director of the China Biodiversity Conservation and Green Development Foundation.

Zhou wants the government to issue public records tracking all living and dead pangolins seized by authorities, and to offer evidence that contraband, including pangolin scales, is destroyed before it enters black markets.

“We are determined to know what happens to the pangolins,” said Sophia Zhang, a researcher at the biodiversity group. After reading news reports about the August 2017 poaching bust, she filed information requests to government agencies and travelled to Guangxi to visit the wildlife rescue Centre.

The Guangxi Forestry Department, which manages the wildlife rescue Centre, declined Associated Press’ requests for an interview and comment. China’s state news agency Xinhua reported in December that China remained committed to stopping pangolin trafficking, noting there were 209 pangolin smuggling busts from 2007 to 2016.

Less official attention has been paid to what happens after these busts.

In Guangxi, Zhang saw that pangolins were kept in small cages and fed cat food at the wildlife centre, whereas wild pangolins eat termites. She said she had tried to coordinate with Save Vietnam’s Wildlife, a non-profit, to bring shipments of termites to feed the pangolins, but the centre declined the offer.

After the animals died, the centre would not reveal what happened to their scaly bodies. But in other instances, the same centre has turned over live pangolins to industry groups, including a steel factory in Guangdong province and a farm associated with a Chinese traditional medicine centre in Jiangxi province. The government released this information on its website.

In response to an information request from Zhang, the Guangxi forestry department sent copies of the licences held by these organisations for handling pangolins. The reason for transferring pangolins remains unclear.

“We want the wildlife centre to provide a full explanation,” Zhang said. “We know the trade in pangolins is very lucrative. The public should be able to know what happens.”

The biodiversity non-profit has filed information requests about trafficked wildlife in nearly 30 Chinese provinces and has attempted to verify what happens to pangolin scales seized by customs officials. Zhang said wildlife rescue centres need better training to properly handle live animals.

“China has a rather complete set of environmental laws,” said Barbara Finamore, the senior strategic director for Asia at the Natural Resources Defence Council in Washington.

“But environmental laws are not worth the paper they’re written on unless there’s also strong enforcement and oversight.”

Countries large and small, rich and poor, have passed extensive green legislation since the Rio Earth Summit in 1992.

“The world has made incredible progress in adopting environmental laws and environmental impact assessments, in creating environmental ministries and agencies,” said Bruch, co-author of the UN report.

Now comes the hard part.

“The legal framework is there in an enormous number of countries,” said Deborah Seligsohn, a political scientist focusing on environmental policy at Villanova University. “But once you have all these laws, you need trained and willing personnel to actually enforce them. You need boots on the ground.”

Green mandates often go unfunded, said Barney Long, director of species conservation at Global Wildlife Conservation, a non-profit group in Austin, Texas.

“Many countries have laws stating the minimum number of park rangers that should be patrolling per square mile in national parks and protected areas. But these aren’t implemented if sufficient money isn’t appropriated.”

Non-governmental groups, like the biodiversity non-profit in Beijing, try to help close the gap between environmental laws and enforcement action. But in many countries, this is dangerous work. In 2017, at least 207 environmental defenders – including forest rangers, advocates, journalists and inspectors – were murdered for performing such work, according to Global Witness, a research and advocacy group based in Washington and London.

There are some bright spots, experts say.

China is gradually releasing more environmental data to the public, especially on air pollution, even as the government clamps down on other forms of information. And more officials are being held accountable, said Jennifer Turner, director of the Woodrow Wilson centre’s China Environment Forum in Washington.

“Before, local officials were only evaluated on economic performance,” she said, “but now it’s harder to hide from environmental sins.”