Most seabirds have already eaten plastic. And it seems the
situation is going to get worse. ‘We predict that plastics ingestion is
increasing in seabirds, that it will reach 99 per cent of all species by 2050,
and that effective waste management can reduce this threat,’ says a study by
Australian and UK scientists published in Proceedings
of the National Academy of Sciences (PNAS), a peer-reviewed US journal. By all
appearances, birds – including albatrosses, penguins and gulls – can mistake brightly
coloured bottle tops, cigarette lighters, toy cars, or other fragments for
food. If ingested, this litter may simply stay in the gut, unable to pass
through, putting the bird’s health at risk.
Researchers reviewed studies on 135 bird species between
1962 and 2012, and then made projections based on the currently known level of
plastics in the oceans. ‘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 Chris Wilcox, senior research scientist at Australia’s
Commonwealth Scientific and Industrial Research Organisation (CSIRO). He goes
on to say, ‘We predict, using historical observations, that 90 per cent of
individual seabirds have eaten plastic. This is a huge amount and really points
to the ubiquity of plastic pollution.’
Researcher Erik Van Sebille says the oceans are now filled
with plastic and it is ‘virtually certain’ that any dead seabird found in 2050 ‘will
have a bit of plastic in its stomach’. Numerous studies have documented the
rising mass of plastic debris being dumped, blown or simply washed out to sea;
and the negative impact on the marine environment is a certainty.
In their PNAS
paper, the scientists reviewed decades of peer-reviewed literature to trace the
evolution of seabirds’ exposure to plastic debris. Going by research done in
the early 1960s, back then less than five per cent of seabirds were found with
waste fragments in their stomach. Today, this figure is roughly 90 per cent. And
currently there is no indication of any reversal in the upward trend.
Ever since commercial plastic production began in the 1950s,
production has doubled every 11 years, according to background information in
the article. ‘Thus, between 2015 and 2026, we will make as much plastic as has
been made since production began,’ the study estimates.
Scientists have documented concentrations of up to 580,000
plastic pieces per square kilometre in the world’s oceans. ‘Although evidence
of population-level impacts from plastic pollution is still emerging, our
results suggest that this threat is geographically widespread, pervasive, and
rapidly increasing,’ the study clarifies.
To get to their 2050 extrapolation, the team performed a
spatial risk analysis using predicted debris distributions and ranges for 186
seabird species to model debris exposure. This has shown that the regions of
highest risk are not where most floating plastic congregates, such as the
infamous garbage patch in the central north Pacific Ocean where the debris just
goes round and round. The highest area of expected impact occurs at the
Southern Ocean boundary in the Tasman Sea between Australia and New Zealand
because of the high plastic concentration and high seabird diversity in those
areas, the study warns.
Another key finding from the research is that the problem is
solvable. Although the short-term prognosis is that plastic impacts are
increasing significantly, analyses also suggest that reductions in exposure
will result in reduced ingestion. Seabirds have the capacity to recover, but first
the stream of plastic waste getting into the oceans will have to be shut off.