As many as nine out of 10 of the world’s seabirds are likely to have pieces of plastic in their guts, a new study estimates.

An Australian team of scientists who have studied birds and marine debris found that far more seabirds were affected than the previous estimate of 29%. Their results were published in the journal Proceedings of the National Academy of Sciences.

“It’s pretty astronomical,” said study coauthor Denise Hardesty, a senior research scientist at the CSIRO.

She said the problem with plastics in the ocean was increasing as the world made more of it. “In the next 11 years we will make as much plastic as has been made since industrial plastic production began in the 1950s.”

Birds mistook plastic bits for fish eggs so “they think they’re getting a proper meal but they’re really getting a plastic meal”, Hardesty said.

Some species of albatross and shearwaters seem to be the most prone to eating plastic pieces.

She combined computer simulations of garbage and the birds, as well as their eating habits, to see where the worst problems are.



Hardesty’s work found the biggest problem was not where there was the most garbage, such as the infamous patch in the central north Pacific Ocean.

Scientists say marine debris will increase as the world makes more plastic. Photograph: Britta Denise Hadety/CSIRO/AP

Instead it was in areas with the greatest number of different species, especially in the southern hemisphere near Australia and New Zealand.

Areas around North America and Europe were better off, she said. By reducing plastic pellets Europe was seeing less of it in one key bird, the northern fulmar.

Hardesty said she had seen an entire glowstick and three balloons in a single short-tailed shearwater bird.

“I have seen everything from cigarette lighters ... to bottle caps to model cars. I’ve found toys,” Hardesty said.

And it is only likely to get worse. By 2050, 99% of seabirds will have plastic in them, Hardesty’s computer model forecasts.

That prediction “seems astonishingly high but probably not unrealistic”, said American University environmental scientist Kiho Kim, who wasn’t part of the study but praised it.