Ninety percent of seabirds have accidentally eaten plastic, and by the middle of this century it will almost impossible to find any that haven't, scientists are predicting.
In 1960, plastic was found in the stomachs of fewer than one in 20 seabirds. This rose to 80 percent by 2010, and according to researchers from Australia, the UK and US, it's only going to get worse – especially in the Tasman Sea.
Despite our clean-green reputation, curator of land vertebrates at Auckland Museum Dr Matt Rayner says it shouldn't be a surprise.
"New Zealand is the global centre of seabird diversity with more endemic seabirds than any other country – 10 percent of all seabirds on the planet breed in and around New Zealand. Many seabirds feed on small prey that is often gelatinous on the surface and thus small pieces of floating plastic are frequently ingested," he says.
"At the Auckland Museum we frequently autopsy seabirds whose stomachs are full of plastic debris."
Scientists looked at studies on plastic ocean pollution published between 1960 and the present to see what effect it's having on ocean wildlife.
Extrapolating the results out to 2050, on current trends they expect 99 percent of seabirds by then will be eating plastic.
"For the first time, we have a global prediction of how wide-reaching plastic impacts may be on marine species – and the results are striking," says Dr Chris Wilcox of Australia-based research institute CSIRO. "We predict, using historical observations, that 90 percent of individual seabirds have eaten plastic. This is a huge amount and really points to the ubiquity of plastic pollution."
The list of things scientists have found inside birds includes plastic bags, bottle caps and plastic fibres from synthetic clothes.
Dr Denise Hardesty, also from CSIRO, once found nearly 200 pieces of plastic in a single bird. She says pollution controls in Europe stemmed the growth of plastic pollution in that part of the world, so New Zealand and Australia should follow suit.
"Even simple measures can make a difference… Improvements in basic waste management can reduce plastic in the environment in a really short time."
In addition to the Tasman, animals that gather around the southern edges of South Africa and South America are also at risk.
The massive conglomerations of plastic found in the middle of the ocean, such as the Great Pacific Garbage Patch, aren't as much of a threat says Dr Erik van Sebille, one of the study's authors.
"We are very concerned about species such as penguins and giant albatrosses, which live in these areas," he says. "While the infamous garbage patches in the middle of the oceans have strikingly high densities of plastic, very few animals live here."
Dr Kyle Morrison, Massey University ecology researcher, says plastic should be treated as serious a threat to marine life as climate change, overfishing and introduced predators.
"Each of us can contribute to reversing the plastic ingestion trend through simple consumer decisions like refusing to use plastic bags and not using 'exfoliating' hygiene products with plastic micro-beads."
Dr Rayner says as apex predators, seabirds are top of the food chain and a good indicator of the ailing health of the marine environment.
"On a local small-scale level, the public should become more concerned with the massive use of plastics in our everyday lives," he says.
"On a global scale we need to be concerned that our politicians are engaged and concerned about such environmental issues as part of a global pollution mitigation strategy." The research is backed by energy giant Shell, as a part of its social investment programme.