While Minister Valli Moosa battles to get South Africans to change their bag habits, an overseas supermarket chain has developed a degradable eco-bag. Emma Brockes investigates whether this will mean the end of the plastic bag as we know it.
In old-fashioned visions of the apocalypse, it used to be the cockroach that was the ultimate symbol of survival. No doomsday scenario was complete without a swarm of the little critters sashaying across a nuclear wasteland, chatting on their cellphones while busily inheriting the Earth.
It is cause for some celebration, then, that the die-hard roach is about to be unseated by a new and more powerful symbol of durability. After the vermin have died, after the uranium has dissolved, even, my God, after the last e-mail has fallen from the supercomputer’s back-up drive, there will be one surviving remnant of civilisation. Human history will be carried through the next ice age in a plastic bag.
Chances are, it won’t come from a supermarket chain in the United Kingdom called the Co-op. This supermarket chain claims to be the first retailer to offer 100% degradable carrier bags at the checkout. By December, two-thirds of all Co-op bags will be made of the new material; if all goes to plan, by 2004 it will be all of them.
The bags look the same, feel the same and have the same carrying qualities as ordinary plastic but, says the Co-op, 18 months after disposal, they melt politely into the ether and cause no further trouble.
The need for 100% degradability is hotly disputed by bag manufacturers — who take the pro-gun lobby line of ”it isn’t plastic bags that kill, but people” — but even they can’t deny that the world has a big bag problem. The life expectancy of a plastic bag is not precisely known.
Polythene was only invented in the 1930s and didn’t become widespread in supermarkets until the 1970s. Figures for its durability range from a conservative 100 years to the recent claim made by Irish supermarket Musgraves of ”one million years”. (Musgraves had just introduced the same line of degradable bags as the Co-op.) Whatever the actual figure, the billions of bags used around the world each day will be in the soil long after their users have returned to the dust.
The landfill space used up thanks to the bags’ longevity is only part of the problem. Plastic bag detractors have a lot of emotive material to play with. Next time you take a fresh bag to carry your one item of shopping in, think of the turtle that might one day mistake it for a tasty jellyfish and die a horrible, asphyxiating death.
Or consider the stretches of coral reef in the Gulf of Aqaba, Jordan, which are being starved to death by the sunlight-blocking layer of plastic that drifts on its surface. Or, if the wildlife angle doesn’t shame you, then what about the 10m of bags that are dumped in the Bangladeshi capital of Dhaka every day and which, by clogging the city’s drains, worsened the effect of recent floods?
Consumers are aware of all this on a vague, emotional level, which manifests itself in something one might call bag-guilt: the sick feeling one gets on opening a kitchen cupboard to an avalanche of polythene that hits us where, in environmental terms, it hurts most — aesthetically. The term ”white pollution” has been coined in China for the tumbleweeds of polythene blowing on the streets.
In South Africa there are so many bags hanging on fences and in the fields that locals say it has become the national flower.
Until recently, most retailers in the United Kingdom responded to the bag mountain either by charging for reusable bags, by making checkout staff inquire whether the customer really needs a bag, or offering money to charity for every bag reused. A bag tax imposed by the government in Ireland last March, which levies 14c per bag, has reduced usage by 90%. But those bags could still be better disposed of.
A company called Symphony Plastics developed the Co-op’s new eco-bag. The bag breaks down thanks to an allegedly harmless decomposition agent, a metal ion that is injected into the polythene mix at the last moment. By varying its concentration, manufacturers can determine the life expectancy of the bag to suit its purpose — to line a pedal bin, say, or to take home the groceries.
Ordinary bags don’t decompose because they are made up of huge, unbreakable molecular chains. Whereas the molecular weight of water is 18 and carbon dioxide is 44, polythene has a molecular weight of around 300 000.
”In the UK, we’ve been working on how to break it down since 1996,” says Michael Stephens, technical director of Symphony Plastics. ”It’s been like the search for a holy grail — a material that performs like normal plastics, is lightweight, has good barrier properties, is printable and strong, but that doesn’t last for decades.”
The technology has been around since the1970s, but there has not been much call for it until now. ”This isn’t a eureka product,” says Stephens. ”There’s an older technology that was based on corn starch and it works, but it has a number of disadvantages.” It never fully disappears, for one, but merely breaks down to a level that is undetectable by the naked eye.
Corn starched plastic is weaker and difficult to make transparent. It also costs three times as much to produce. ”Commercially, it was a bit of a disaster,” says Stephens.
The new technology, by contrast, reduces the molecular weight of the plastic from 300 000 to 4 000, at which point it can be consumed by micro-organisms. It is degradable rather than biodegradable because it does not rely on a living organism to act as catalyst. You could shove it in a sealed drawer and it would still, eventually, disappear.
The cost has also been broken down. ”There is negligible expense for the retailer,” says Martin Henderson of the Co-op, ”and it is not one we would seek to recoup.”
Still, doubts about the value of the product remain, largely among the vested interests of the polythene industry but also, more surprisingly, with some environmentalists. Peter Woodall, a representative of the UK’s Packaging and Industrial Films Association, is scathing: ”If you look at the very first rule of sustainability, the [eco-bag makers] break it by producing something that goes to waste instead of following the rules of reduce, reuse and recycle, which is what good environmental practice is all about.
”There are also concerns about contamination of existing recycling schemes. We don’t know what this material releases when it breaks down. The feeling of the polymer industry is that biodegradable materials are good for certain applications, for example, home composting, and in agriculture, but that in the general consumer stream they could represent serious long-term problems.”
It’s about money, too, isn’t it? ”My sense is that yes, they are considerably more expensive to make — and for no good environmental reason,” says Woodall.
This argument — that the plastic bag might do more environmental damage by breaking down than by hanging around the landfill until doomsday — is dismissed by Stephens as ”embarrassing” and ”in the Dark Ages”. The by-products of the degradable bag are water and a small amount of carbon dioxide, he says. ”There is a good chance that our bags will disintegrate before they get to the bottom of the landfill, where the carbon is turned into dangerous methane.”
At Friends of the Earth, the degradable bag has been grudgingly accepted as a small, positive step on a very long road. ”We welcome the initiative,” says Mike Childs, ”because bags do a lot of damage to wildlife and litter is obviously a problem.” But with the hard charity of the purist, he has reservations: ”In some ways, it’s a bit of a con because there are bigger environmental problems than plastic bags.”
Even the bag tax doesn’t meet with wholehearted approval. ”Ask people across Europe if the Irish are good on environment and they’ll say they’re fantastic, they’ve got this bag scheme,” says Childs. ”Whereas actually they are one of the worst countries in Europe for disposing of waste. They’ve got large numbers of landfills that aren’t properly controlled and they want to build lots of incinerators. There’s a danger this will be used as a tool by the spin doctors to make it look as if a government is doing a lot when in fact it is doing very little.”
If the experiment at the Co-op is successful, scientists at Symphony Plastics want to extend the technology to other packaging — bubble wrap, frozen-food bags, bread bags. The supermarket supports the imposition of a bag tax, and Henderson suggests that the government lower the rate on degradable bags to encourage wider use.
Whatever happens, environmentalists and retailers alike recognise that, when trying to change consumer habits, it is best to take as pessimistic a view of human nature as possible.
In the first few months after the bag tax was introduced in Ireland, shoppers were seen carrying their groceries out in their jerseys, a lot of wire baskets went missing — and it is safe to assume that the fate of the turtles was a very long way from everyone’s minds. —