Is it reaching a tipping point for the earth?
From:
Stockholm University
July 1, 2021 -- Current rates of plastic
emissions globally may trigger effects that we will not be able to reverse,
argues a new study. According to the authors, plastic pollution is a global
threat, and actions to drastically reduce emissions of plastic to the
environment are 'the rational policy response.'
Plastic is found everywhere on the
planet: from deserts and mountaintops to deep oceans and Arctic snow. As of
2016, estimates of global emissions of plastic to the world's lakes, rivers and
oceans ranged from 9 to 23 million metric tons per year, with a similar amount
emitted onto land yearly. These estimates are expected to almost double by 2025
if business-as-usual scenarios apply.
"Plastic is deeply engrained in our
society, and it leaks out into the environment everywhere, even in countries
with good waste-handling infrastructure," says Matthew MacLeod, Professor
at Stockholm University and lead author of the study. He says that emissions
are trending upward even though awareness about plastic pollution among
scientists and the public has increased significantly in recent years.
That discrepancy is not surprising to
Mine Tekman, a PhD candidate at the Alfred Wegener Institute in Germany and
co-author of the study, because plastic pollution is not just an environmental
issue but also a "political and economic" one. She believes that the
solutions currently on offer, such as recycling and cleanup technologies, are
not sufficient, and that we must tackle the problem at its root.
"The world promotes technological
solutions for recycling and to remove plastic from the environment. As
consumers, we believe that when we properly separate our plastic trash, all of
it will magically be recycled. Technologically, recycling of plastic has many
limitations, and countries that have good infrastructures have been exporting
their plastic waste to countries with worse facilities. Reducing emissions
requires drastic actions, like capping the production of virgin plastic to
increase the value of recycled plastic, and banning export of plastic waste
unless it is to a country with better recycling" says Tekman.
A poorly reversible pollutant of remote
areas of the environment
Plastic accumulates in the environment
when amounts emitted exceed those that are removed by cleanup initiatives and
natural environmental processes, which occurs by a multi-step process known as
weathering.
"Weathering of plastic happens
because of many different processes, and we have come a long way in
understanding them. But weathering is constantly changing the properties of
plastic pollution, which opens new doors to more questions," says Hans
Peter Arp, researcher at the Norwegian Geotechnical Institute (NGI) and
Professor at the Norwegian University of Science and Technology (NTNU) who has
also co-authored the study. "Degradation is very slow and not effective in
stopping accumulation, so exposure to weathered plastic will only increase,"
says Arp. Plastic is therefore a "poorly reversible pollutant," both
because of its continuous emissions and environmental persistence.
Remote environments are particularly
under threat as co-author Annika Jahnke, researcher at the Helmholtz Centre for
Environmental Research (UFZ) and Professor at the RWTH Aachen University
explains:
"In remote environments, plastic
debris cannot be removed by cleanups, and weathering of large plastic items
will inevitably result in the generation of large numbers of micro- and
nanoplastic particles as well as leaching of chemicals that were intentionally
added to the plastic and other chemicals that break off the plastic polymer
backbone. So, plastic in the environment is a constantly moving target of
increasing complexity and mobility. Where it accumulates and what effects it
may cause are challenging or maybe even impossible to predict."
A potential tipping point of
irreversible environmental damage
On top of the environmental damage that
plastic pollution can cause on its own by entanglement of animals and toxic
effects, it could also act in conjunction with other environmental stressors in
remote areas to trigger wide-ranging or even global effects. The new study lays
out a number of hypothetical examples of possible effects, including
exacerbation of climate change because of disruption of the global carbon pump,
and biodiversity loss in the ocean where plastic pollution acts as additional
stressor to overfishing, ongoing habitat loss caused by changes in water
temperatures, nutrient supply and chemical exposure.
Taken all together, the authors view the
threat that plastic being emitted today may trigger global-scale, poorly
reversible impacts in the future as "compelling motivation" for
tailored actions to strongly reduce emissions.
"Right now, we are loading up the
environment with increasing amounts of poorly reversible plastic pollution. So
far, we don't see widespread evidence of bad consequences, but if weathering
plastic triggers a really bad effect we are not likely to be able to reverse
it," cautions MacLeod. "The cost of ignoring the accumulation of
persistent plastic pollution in the environment could be enormous. The rational
thing to do is to act as quickly as we can to reduce emissions of plastic to
the environment."
https://www.sciencedaily.com/releases/2021/07/210701140931.htm
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