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Battle of the bag

New Scientist vol 183 issue 2464 - 11 September 2004, page 30

I'M NOT a bad person. I've adopted a dolphin from the WWF and a lemur from my local zoo. I buy organic milk, free-range eggs and always put the recycling out on a Thursday. But take a look in my kitchen and you will find that I have a dirty environmental secret. Lurking under the sink is a strangely inexhaustible stash of plastic bags. Twenty-eight of them to be precise, and that doesn't include the shiny ones with good handles that I've kept for a special occasion. And I'm not alone. Most households have dozens stuffed into a drawer or cupboard. You can even buy holders to keep them in one place for that elusive day when you remember to reuse them.

It may not sound like the worst crime known to humankind, but for a growing number of environmentalists the humble plastic bag has become public enemy number one - an unnecessary evil that must be stopped. Discarded carrier bags not only litter our towns and countryside, they kill wildlife, block drains and hang around in the environment for decades. Landfill operators dislike them for their annoying habit of being blown off-site. The general public, too, seems to be embracing the anti-bag mood, and governments the world over have joined the fight, with countries from India to Ireland doing their bit towards a common goal - to sack the carrier bag for good.

The only people who have a good word to say about plastic bags are the plastic-bag industry. Big surprise, you might say. But cast aside any suspicion of vested interest, and the industry's arguments start to make sense. Objectively, plastic bags are nowhere near the world's worst environmental problem. The reason they are being picked on, the industry claims, is because they are an easy and emotive target that panders to our guilt about general environmental irresponsibility. In fact, there is scant evidence that banning the plastic bag would have any benefits. So who is right?

Since it was introduced in the 1970s the plastic bag has become a part of our lives, and today most people around the world don't use anything else to carry their shopping. Depending on who you ask, the UK gets through somewhere between 9 billion and 17 billion plastic bags a year (see Figure). Globally, we carry home between 500 billion and a trillion every year. That is 150 bags a year for every person on Earth, or, to put it another way, a million a minute and rising.

Startling as these statistics are, they don't explain why plastic bags have become so hated. For that you have to turn to the claims of the environmental movement. While bags may be, in the words of the British Plastics Federation, "a hygienic, odourless, waterproof, robust and convenient way of carrying goods", greens argue that they are environmentally unsound in pretty much every way, and that we don't really need them. "They are a waste of resources in that we use them once and throw them away, and there is absolutely no reason to have this one-usage approach to bags," says Claire Wilton, senior waste campaigner for Friends of the Earth in London.

"Plastic bags exceed what you would anticipate would be their pollution impact, because they're so much more mobile than other types of litter," says Samantha Fanshawe, the UK Marine Conservation Society's director of conservation. Once they are free they become a highly visible problem, blustering around the streets or flapping annoyingly in the branches of trees. This irritating habit has earned them a variety of pejorative nicknames round the world: "witches' knickers" in Ireland, "white pollution" in China and the "national flower" in South Africa. Plastic bags can also have a devastating effect on wildlife. "There have been a number of cases recently where dead turtles and whales have been washed up with plastic bags blocking their guts," Fanshawe says. "We are getting a couple a year in northern European waters. There's no doubt it is increasing."

The latest victim was a filter-feeding minke whale washed up in Normandy in 2002 with 800 kilograms of plastic bags and other packaging in its stomach. And since most marine animals die far out at sea and autopsies on beached carcasses are relatively rare, the real death toll may be much higher. The Planet Ark Environmental Foundation, based in Sydney, Australia, estimates that tens of thousands of whales, birds, seals and turtles are killed every year from plastic bag litter, thanks in no small part to the way that a floating carrier bag looks - to a turtle at least - like a tasty jellyfish.

Drastic action

And it seems as though even the smallest creatures are at risk. A study published in Science in May (vol 304, p 838) found that there has been a significant rise in plastic fragments in marine sediments over the past 40 years, which small invertebrates like barnacles are more than capable of eating. About 6 per cent of the plastic is polyethylene. Richard Thompson from the University of Plymouth in the UK, who led the study, says: "My feeling is that plastic bags will almost certainly contribute to the microplastics we're finding."

The Danes were among the first to try putting a stop to it in 1994 when they introduced a tax on all packaging, including carrier bags. This led to a 66 per cent drop in take-up at the checkout, despite the fact that it was the supermarkets and not their customers who had to pay up. Taiwan followed in 2001, charging about 2 pence for a plastic bag. The levy was criticised by industry and the public as being confusing and unfair but still managed to slash plastic bag usage by 69 per cent.

In 2002, Bangladesh took a more drastic approach, bringing in a total ban on the production and sale of polyethylene and introducing a £5 on-the-spot fine for using a plastic bag. If a blanket ban seems a little extreme, it was prompted by more than just green thinking. In a country with limited waste disposal and virtually no bins, most of the 10 million or so plastics bags used every day were dropped in the street, then washed into rivers and sewers where they choked the country's drainage system. The Buriganga river, which flows through the capital Dhaka, was left almost dammed by plastic bags, and blocked drains are widely held responsible for the devastating monsoon floods of 1988 and 1998. In the two years since the ban, the once floundering jute-bag industry has been resurrected and street children are reportedly doing a roaring trade in handmade paper bags made from newspaper and torn-up exercise books. A resurgence of rebel plastic-bag manufacturers this year has prompted a government crackdown, with manufacturers facing up to 10 years in jail and a fine of £9000.

The government of the north Indian state of Himachal Pradesh is also taking a hard line. There, being caught in possession of a polyethylene bag could get you seven years behind bars and a £1000 fine.

Elsewhere, governments rich and poor are having a bash at binning the bag. Last year, in a bid to promote stronger, reusable alternatives, South Africa made carrier bags thinner than 30 micrometres illegal. The average supermarket carrier is about 18 micrometres thick. In China, supermarkets have so far resisted plans to make them charge for plastic bags, but the government has promised more effective enforcement later this year. Meanwhile in Australia, Planet Ark's high-profile campaign, featuring stars such as Pierce Brosnan and Dannii Minogue, has struck a chord with the public, and several towns have opted to go "plastic free" while they wait for the government's decision on how to kick the nation's 6-billion-a-year habit.

In 2002, Ireland introduced a levy of 15 cents on plastic carriers, payable by the consumer. Within months the number of bags taken fell by 90 per cent, and in the two years since then, the "PlasTax" has raised €23 million for environmental projects. Mike Pringle, a member of the Scottish parliament, is lobbying for a similar tax. But the UK's central government is not convinced. Its latest word is that "a levy would not necessarily be beneficial to the environment", and that "policy...is focused on changing the way in which the waste stream as a whole is managed".

But before anyone criticises the UK government for lagging behind world opinion, it is worth considering that it does, in fact, have a point. Yes, bags harm the environment, but they are a small part of a much bigger problem. According to the UK government's calculations, plastic bags account for less than 1 per cent of the rubbish sent to landfill. In a world where pretty much everything is disposable, aren't there more deserving targets for our environmental wrath?

"Plastic bags are certainly not the biggest part of the waste stream," Wilton admits. "They're not even the biggest part of the household waste stream, and that isn't the biggest part of our overall waste."

Similarly, plastic bags make up only a tiny proportion of litter. The Marine Conservation Society's 2003 Beachwatch Survey calculated that while plastics made up 56 per cent of the total litter found on beaches around the UK, carrier bags accounted for only 2 per cent of all the litter. Plastic bottles featured higher in the list, as did fishing waste and sewage. Less than 1 per cent of litter in general is plastic bags.

No wonder critics of the war on plastic bags claim that the environmental impact is vastly overstated, and that banning or taxing carrier bags produces no net environmental gain. It just shifts the problem elsewhere. More people have to buy "proper" rubbish bags instead of reusing their supermarket carriers, and bulkier waste is produced as shops turn to paper bags and cardboard boxes.

According to the Carrier Bag Consortium, a group of UK suppliers set up to fight the anti-bag campaign, the Irish bag tax has done nothing to reduce the consumption and disposal of plastic bags. It also points out that plastic bags have among the highest reuse rates of any disposable product - 80 per cent are recycled at least once as bin liners and nappy bags, and by dog owners for scooping the poop. What is more, they are much more energy-efficient to manufacture and transport than bulkier, heavier alternatives like paper and cardboard. And once they've been thrown away, some of the energy used to make them can be recovered by incinerating them in energy-from-waste plants.

So if plastic bags aren't as bad as they are made out to be, are governments and green campaigners jumping on the wrong bandwagon? Well, yes and no. While the plastic carrier may have been made a scapegoat, it is also true that if you want people to think about sustainability, an everyday object that most of them already feel guilty about is a good place to start. "Plastic carrier bags are symbolic of a society in which we use things without thinking and then throw them away," Wilton says. "Because of this governments have realised that, by focusing on something so symbolic, they can get messages across to people about their behaviour and how it has an impact on the environment."

The plastic bag industry, unsurprisingly, takes issue with being blamed for general environmental irresponsibility. But even with the facts on their side manufacturers seem resigned to taking a beating. "Green marketing wins out every time," bemoans Carrier Bag Consortium spokesman Peter Woodall.

While the two sides bicker over whether plastic is better or worse than paper for carrying our shopping, they do at least agree on one thing: biodegradable bags are not the answer. "It may actually encourage wrong attitudes to litter prevention and does not contribute to environmental sustainability," says a statement by the UK's Packaging and Industrial Films Association, based in Nottingham. "Biodegradable bags make people feel better for doing something that is still unhelpful, and it's not actually tackling the bigger problem of wasting resources," Wilton says. And to your average turtle, a degradable bag looks just as much like a jellyfish as a non-degradable one.

Perhaps the compromise is to follow the lead of the bag-snaggers of New York. With their patented bag-snagging device - a hook on a telescopic pole - writer Ian Frazier and friends have turned collecting tree-top litter into the coolest urban sport in America. Now there's a fun and practical solution everybody can live with.