More than 90 per cent of oil slicks threatening global marine life caused by humans, US and Chinese scientists find

Article in Science journal reveals major shift from 1990s estimate showing roughly 50-50 split in human and natural sources

Governmental collaboration key to preventing the global problem threatening marine ecology and food safety, co-author says

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A heavily oiled bird is rescued from waters affected by the Deepwater Horizon oil spill, in June 2010. Photo: AP

Published: 2:00am, 17 Jun 2022

More than 90 per cent of chronic oil slicks in the world’s oceans come from human sources, not just half as previously thought, new satellite image analysis indicates.

Ships, oil platforms and pipelines were responsible for as much as 94 per cent of the ecologically damaging phenomenon, while only the remaining 6 per cent came from natural seeps, researchers from China and the United States wrote in a recently published article.

Their findings show a major shift from an estimate by the US National Research Council that found a roughly 50-50 split in human and natural sources by slick area in the 1990s, the team said.

Oil slicks are thin layers of oil on the ocean surface that are continuously produced by human activities and natural seepages from the sea floor.

Massive oil spills could also cause them. In 2010, a staggering 4 million barrels of oil were released in the largest marine oil spill in history after the Deepwater Horizon drilling rig in the Gulf of Mexico exploded and sank, claiming 11 lives.

And last year, 9,400 tonnes of oil spilled into the Yellow Sea after a tanker collision off the Chinese port city of Qingdao, polluting nearly 800km of coastline, according to an investigation report released in January. Chinese authorities said it would take at least 10 years for fishing resources to recover to the pre-pollution level.

For the latest study, scientists from China’s Nanjing University, and the South Florida and Florida State universities in the US analysed more than 560,000 images of global oceans from 2014-19, taken by the European Space Agency’s Sentinel-1 satellite.