In 2014, 8.5 billion single-use plastic bags were used by customers in UK supermarkets alone. This is more than 58,000 tonnes of plastic, most of which would have ended up in landfill or as litter along roads and in waterways. The environmental consequences of this are clear: synthetic plastic bags can take centuries to decompose, while those that block waterways and drainage systems have a more immediate effect, and cause harm to wildlife who may ingest or get entangled in them.
It is not surprising therefore that governments and organisations around the world have tried to curb their use through bans or mandatory charges but have these tactics been successful?
Our research has found that, yes, the five pence charge has been effective in reducing plastic bag use across the country. Not only that, it has also made people think more about the environment, and as a result they have become more supportive of other environmental policies.
Mandatory bag charges have been shown to be popular among the public. The economist Frank Convery and his colleagues even call the Irish plastic bag levy the most popular tax in Europe, and say that the plastax is so popular it would be politically damaging to remove it.
The environment is a devolved policy area in the UK, and so the regional governments have introduced charges at different times over the past five years. Wales was the first to introduce a five pence single-use carrier bag charge in October 2011, followed by Northern Ireland in April 2013, and Scotland in October 2014. England then introduced its charge on single-use plastic bags sold by large retailers in October 2015.
The plastic bag charge is a good example of how devolution provides an opportunity to develop policies in one part of the UK before rolling them out to the other parts. In effect, the UK has become a ready-made natural laboratory to test which policies work. We took this idea and used it to examine how the English plastic bag charge has changed shopper behaviour. Our researchers conducted nationally representative surveys, and asked a participants to keep a diary after which we interviewed them about their shopping habits. We also observed shoppers leaving supermarkets. We did this before and after the plastic bag charge was introduced in England, and then compared the results with Wales and Scotland where charges were already in place.
We found the charge was highly effective. The majority of supermarket shoppers in England (57%) used single-use plastic bags beforehand, but this fell to only 21% after the charge was introduced the same level as in Wales (18%). Most of the shoppers replaced single-use plastic bags with reusable bags for life after the policy was implemented.
It was surprising to see how quickly the change took place. Already one month after the introduction of the charge, plastic bag use in England was indistinguishable from plastic bag use in Wales and Scotland. So how was this tiny charge so effective in changing behaviour?
A plastic bag charge is usually seen as an economic instrument, that is, an incentive to incorporate an environmental cost into the household budget. Indeed, we found that some people changed their behaviour to avoid paying the charge, and so increasing their expenditure. For most people, however, the charge acted as a habit disruptor. Before its implementation many shoppers would just simply forget to bring their own bag to the supermarket. We found that the charge made people stop and think about waste, and whether they really need to use a single-use plastic bag for their shopping.
Furthermore, it appears that plastic bag charges become more popular after they are introduced. In England, a majority (52%) already supported the charge before it was introduced, and support increased to 60% one month after. A similar effect was found in Wales in 2011. One reason why people became more positive is that it has been easy for them to adapt to the charge. Shoppers quickly found new routines, such as keeping bags in the boot of the car, to help remember to take them to the supermarket.
There were some other, unexpected effects too: not only did people become more supportive of a plastic bag charge after they experienced it, they also became more supportive of other charges to reduce waste. Support for a hypothetical charge on water bottles increased from 34% to 40% across the UK, for example. In particular, those who changed their opinion about the plastic bag charge also changed their opinion about other charges.
And so it seems that the plastic bag charge has paved the way for other measures to reduce waste. Now may therefore be the right time to trial other waste reduction policies, such as a deposit return scheme or a charge on disposable coffee cups.
Photo by mastermaq