Degrading plastics are contributing to climate change: Scientists discover some greenhouse gases are produced when plastics are exposed to sunlight
- Polyethylene from carrier bags is a leading producer of methane and ethylene
- These are greenhouse gases that contribute to atmospheric warming
- Sunlight causes the polymers to slowly degrade and it continues even in the dark
- The production of these chemicals from plastic degradation is not accounted for in any models of plastic pollution or greenhouse gas levels
The plastic pollution plot thickens as scientists reveal that sunlight forces plastic to decompose and release greenhouse gases into the atmosphere.
Methane and ethylene are commonly created by the natural degradation of a variety of commercial plastic waste.
Polyethylene, the polymer used in carrier bags, was the worst offender and most likely to create high volumes of atmospheric pollutants, researchers found.
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The plastic pollution plot thickens as scientists reveal that sunlight forces the waste to decompose and release greenhouse gases into the atmosphere. Methane and ethylene are commonly created by the natural degradation of a variety of commercial plastic waste
The study, published today in PLOS ONE, focused on how plastics behave when subject to prolonged bouts of sunlight.
The University of Hawaii researchers tested polycarbonate, acrylic, polypropylene, polyethylene terephthalate (PET), polystyrene, high-density polyethylene (HDPE) and low-density polyethylene (LDPE).
These plastics are used in plastic pipes, food packaging, carrier bags and textiles, among others.
Polyethylene, used in shopping bags, is the most widely produced and discarded synthetic polymer globally.
It is also the most prolific emitter of both methane and ethylene, which warm the atmosphere and contribute to global warming.
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Initiated by solar radiation, the breaking down and emission of gases continued even in the dark, researchers found.
Study senior author Professor David Karl, of the University of Hawaii at Manoa School of Ocean and Earth Science and Technology, said: ‘Plastic represents a source of climate-relevant trace gases that is expected to increase as more plastic is produced and accumulated in the environment.
‘This source is not yet budgeted for when assessing global methane and ethylene cycles – and may be significant.’
Production of plastics – which started nearly 70 years ago – is expected to double over the next two decades.
Their durability and low cost makes them attractive even though they are known to release a variety of chemicals during degradation – endangering organisms and ecosystems.
BREAK THE PLASTIC HABIT! JOIN THE DAILY MAIL’S CAMPAIGN
Ten years ago, the Mail launched a trailblazing campaign to rid Britain of the scourge of plastic supermarket bags — prompted by a heartrending, shaming picture of an endangered turtle entangled in one, which was used on the front page.
The success of our Banish The Bags initiative has been nothing short of phenomenal.
Now, in a landmark series that could have just as big an impact as that front page a decade ago, we’re here to assure you that you really can make a difference — and your actions can help save our beautiful world and its animals.
The Mail’s Turn The Tide On Plastic campaign isn’t intended to make you feel guilty about plastic you depend on. Instead, this series will guide you through small daily steps you can take — with little expense or effort — to make dramatic inroads into reducing the amount of plastic you use.
Even simply changing one habit — such as using the reusable coffee cup we’re giving away today, instead of a throwaway cup — will help decrease the demand for new plastics. If every Daily Mail reader uses their cup just once a day in place of a takeaway cup, millions of plastic-lined paper cups will be saved from landfill in a year.
It’s simple maths. Use a plastic bag twice and you halve your plastic footprint. Buy one bar of soap and you may spare the planet two or even three pump-action hand wash bottles. Inspire someone else and the impact is doubled.
We’ll tell you how to double your recycling efficiency overnight, banish plastic from your kitchen and dodge food packaging. Better yet, you can even shop to save the planet with gorgeous — and reusable — plastic alternatives.
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Polyethylene, the polymer used in carrier bags, was the worst offender and most likely to create high volumes of the atmospheric pollutants. The US team described the discovery reported as ‘unexpected’
The US team described the discovery as ‘unexpected.’
The researchers also found the emission rate of the gases from virgin pellets of LDPE increased during a 212-day experiment.
Lead author Dr Sarah-Jeanne Royer, of the Centre for Microbial Oceanography at Hawaii University, said: ‘We attribute the increased emission of greenhouse gases with time from the virgin pellets to photo-degradation of the plastic, as well as the formation of a surface layer marked with fractures, micro-cracks and pits.
‘With time, these defects increase the surface area available for further photo-chemical degradation and therefore contribute to an acceleration of the rate of gas production.’
She said smaller ‘microplastics’ – tiny particles that are eventually produced in the environment by degradation – could further accelerate greenhouse gas production.
Production of plastics – which started nearly 70 years ago – is expected to double over the next two decades. The production of greenhouse gases from plastic degradation is not yet budgeted for when assessing global methane and ethylene cycles – and may be significant’
HOW DO MICROPLASTICS GET INTO THE OCEANS FROM RIVERS?
Urban flooding is causing microplastics to be flushed into our oceans even faster than thought, according to scientists looking at pollution in rivers.
Waterways in Greater Manchester are now so heavily contaminated by microplastics that particles are found in every sample – including even the smallest streams.
This pollution is a major contributor to contamination in the oceans, researchers found as part of the first detailed catchment-wide study anywhere in the world.
This debris – including microbeads and microfibres – are toxic to ecosystems.
Scientists tested 40 sites around Manchester and found every waterway contained these small toxic particles.
Microplastics are very small pieces of plastic debris including microbeads, microfibres and plastic fragments.
It has long been known they enter river systems from multiple sources including industrial effluent, storm water drains and domestic wastewater.
However, although around 90 per cent of microplastic contamination in the oceans is thought to originate from land, not much is known about their movements.
Most rivers examined had around 517,000 plastic particles per square metre, according to researchers from the University of Manchester who carried out the detailed study.
Following a period of major flooding, the researchers re-sampled at all of the sites.
They found levels of contamination had fallen at the majority of them, and the flooding had removed about 70 per cent of the microplastics stored on the river beds.
This demonstrates that flood events can transfer large quantities of microplastics from urban river to the oceans.
Greenhouse gases directly influence climate change – affecting sea level and global temperatures along with ecosystem health on land and in the ocean.
They also trigger storms which increase flooding, drought and erosion.
Dr Royer said: ‘Considering the amounts of plastic washing ashore on our coastlines and the amount of plastic exposed to ambient conditions, our finding provides further evidence that we need to stop plastic production at the source – especially single use plastic.’
She is now working to develop estimates of the amount of plastic exposed to the environment in oceanic and terrestrial regions across the world in order to constrain the overall greenhouse gas emissions from plastics.
Plastics have a devastating impact on the planet, with them interfering with ecosystems around the world.
The Daily Mail led calls for a charge to reduce the numbers of plastic bags, and is campaigning for the introduction of a deposit return scheme to reduce the vast numbers of plastic bottles dumped in our rivers and seas – harming wildlife.
Millions of tons of plastic rubbish ends up in the sea each year.
But at the moment, emissions from dumped plastic is not included in estimates of greenhouse gas emissions.
A big drop in plastic bags found in the seas around Britain has been credited to the introduction of charges for plastic bags across Europe.
Ireland and Denmark were the first two countries to bring in levies for plastic bags from shops in 2003, followed by slew of other European countries.
England was the last UK nation to introduce one, in 2015.
Earlier this year British scientists found a 30 per cent drop in plastic bags on the seabed in a large area from close to Norway and Germany to northern France and west to Ireland.
The researchers said the drop in plastic bag pollution measured from 2010 – about the mid-point of charging policies coming into force – showed the power of such levies.
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