Right: No mistaking the message on this shopper's bag.
Arguments in favour of banning plastic bags
1. Plastics, including plastic bags, are a hazard to animal and human life
Environmentalists are concerned about the harm that plastics are doing to the wildlife, especially marine life. Plastic bags are mistaken as food and consumed by a wide range of marine species, especially those that consume jellyfish or squid, which resemble plastic bags when floating in the water column.
International studies on the impact of plastic on marine life and birds are often only estimates as it is difficult to track where all plastic bags end up and observe what happens to every whale, dolphin and turtle that swallows them.
The contents of the stomaches of dead marine animals have been examined and these have suggested the harm that plastics are doing. A total of 177 marine species are known to ingest plastic litter. Ingestion of litter such as plastic bags can cause physical damage to the oesophagus, mechanical blockage of the digestive system, and a false sensation of feeling full. This can lead to infections, starvation and death.
In August 2000, an autopsy of an eight-metre bryde's whale beached at Trinity Bay near Cairns revealed a tightly compacted ball of plastic debris in the animal's stomach. The contents included 33 different items made up mainly of plastic bags, as well as noodle packages. In total there was nearly six square metres of plastic in the whale's stomach.
Sea turtles are especially affected by the presence of plastic debris. They ingest different types of floating objects including condoms, balloons and fishing line, as if they were food. In 1998, an autopsy carried out on the body of a juvenile green turtle found washed up on Lennox Head Beach in northern NSW revealed a complete bowel blockage caused by a piece of black plastic the size of an open palm. Above the blockage food putrefied and slowly poisoned the animal to death.
The Australian Federal Government's Threatened Species Scientific Committee has found plastic bags and other marine debris are a direct threat to 20 marine species, including the loggerhead turtle, southern right whale, blue whale and tristan albatross. It has listed plastic bags as a Key Threatening Process under the Environment Protection and Biodiversity Conservation Act 1999.
It has been claimed by some critics that the impacts on human health are perhaps the most serious of the effects associated with plastic grocery bags and that these range from health problems associated with emissions, to death.
It has been claimed that the emissions associated with plastic bag manufacture and distribution are a major health hazard. These toxic emissions have been said to contribute to acid rain, smog, and numerous other harmful effects associated with the use of petroleum, coal, and natural gas. These harmful effects include the effect on the health conditions of coal miners and environmental impacts associated with natural gas and petroleum retrieval.
In 2005, the city of Mumbai, India experienced massive monsoon flooding, resulting in at least 1,000 deaths, with additional people suffering injuries. City officials blamed the destructive floods on plastic bags which clogged gutters and drains, preventing the rainwater from leaving the city through underground systems.
Similar flooding happened in 1988 and 1998 in Bangladesh, which led to the banning of plastic bags in 2002.
By clogging sewer pipes, plastic grocery bags also create stagnant water; stagnant water produces the ideal habitat for mosquitoes and other parasites which have the potential to spread a large number of diseases, such as encephalitis and dengue fever, but most notably malaria.
It has been noted that the effects of plastic bags are most severely felt in poor and rural areas, where shopping bags are dispensed and used widely but not disposed of properly.
2. Australia's use of plastic bags is excessive
Twenty million Australians use almost 7 billion plastic bags a year - nearly one plastic bag per person per day. Fifty three per cent of these bags come from big supermarkets and the rest from other retailers.
Of these approximately 6.9 billion plastic bags consumed annually in Australia, 6 billion are high density polyethylene (HDPE) such as supermarket singlet bags, and 0.9 billion are low density polyethylene (LDPE) such as boutique bags. It is claimed that this level of use of plastic bags is excessive and unsustainable. It is further claimed that the bags are not even a significant contributor to the Australian economy as 67% of the HDPE bags are imported.
It has also been claimed Australia's use of plastic bags is part of a world-wide pattern of excessive use of this product. Single use plastic bags are now consumed at a rate of approximately 500 billion per year globally, or 1 million per minute. It is estimated that 1% or 5 billion of these bags end up as wind blow litter each year. These bags, that can take up to 1,000 years to biodegrade, often wind up in waterways or the landscape, becoming eyesores and eventually degrading water and soil as they break down into tiny toxic bits.
3. Plastic bags are a waste of resources
Plastic bags' manufacture and disposal uses large quantities of non-renewable resources, especially petroleum. Large amounts of global warming gases are released during their production, transportation, and disposal. Hundreds of thousands of marine animals, including endangered sea turtles, die every year when they eat plastic bags mistaken for food.
The following information comes from a publication titled, 'Plastic Grocery Bags: The Ecological Footprint' and brought out under the auspices of the Vancouver Island Public Interest Research Group.
'The lifecycle of a plastic grocery bag begins with the extraction and processing of raw materials ... The process of manufacturing plastic grocery bags requires significant quantities of both energy and raw materials. Two plastic bags require 990 kilojoules of natural gas, 240 kilojoules of petroleum, and 160 kilojoules of coal. Additionally, there are large amounts of energy used to acquire oil, such as the large, fuel-burning heavy machinery, and most of the electricity used in the process of manufacturing the actual bags comes from coal-fired power plants ...
The key ingredients in plastic bags are petroleum and natural gas, and the manufacturing of plastic bags accounts for 4 per cent of the world's total oil production ...
Following manufacturing, the plastic grocery bags are subsequently shipped all over the world. Australia alone imports 4 billion bags annually. Container ships used to transport these bags to each consumer country use fuels which produce high levels of pollutants, such as sulphur.
Annual trips multiply this environmental damage as manufacturers try to accommodate the increasing demand to numerous countries.'
Opponents of plastics bags argue that to use so many non-renewable resources in the production of a product whose use is discretionary is unacceptably wasteful.
4. There are alternatives to plastic bags
There are alternatives to the common single-use plastic bag and the most encouraging progress is being made with biodegradable bags, often made from cornstarch. There are a variety of cotton and calico bags. There are also different types and gauges of paper bag, some of which are reusable. There are also a variety of starch based bags. Again, depending on the gauge of bag these are also able to be used more than once.
A report by the Department of the Environment and Heritage, Plastic Shopping Bags - Analysis of Levies and Environmental Impacts (2002) includes a table which lists 10 bag types and their environmental impacts. The table includes the single use plastic bag through to paper and 'green' bags, comparing the amount of material consumed: the potential for litter; the amount of energy consumed in manufacture and the greenhouse impact.
Polypropylene bags, like the 'Green Bags' seen in Coles and Woolworths supermarkets, are made from non-woven polypropylene that is manufactured from polypropylene gas, a by-product of oil refining. These reusable bags often have a solid removable base that is manufactured from nylon or PET.
Polypropylene bags can carry more shopping than plastic check-out bags, so shoppers use less. They are sturdy and designed to be reused repeatedly. They have a lifespan of up to three years and can be recycled.
Polypropylene bags reduce consumption (and therefore environmental impacts) of single use bags and may encourage customers to be more 'waste-wise' in daily life.
5. Plastic bags pose a major waste disposal problem
Eighteen years of Clean Up Australia Day has clearly demonstrated the impact plastic bags are having on the environment. A survey of the rubbish collected is done each year and plastic bags are among the most common plastic items found on Clean Up Australia Day year after year. More than half of the tens of thousands of plastic bags collected on Clean Up Australia Day are found on beaches, waterfront areas, in rivers and creeks.
Two national opinion polls in a row have shown overwhelming public support for a ban on plastic bags in Australia and a growing number of communities are introducing their own bans.
In 2002 around 50 to 80 million bags ended up as litter in our environment. While the number littered has probably been reduced since then, it is likely that a large number still enter the environment.
Although plastic bags make up only a small percentage of all litter, the impact of these bags is nevertheless significant. Plastic bags create visual pollution problems and can have harmful effects on aquatic and terrestrial animals. Plastic bags are particularly noticeable components of the litter stream due to their size and can take a long time to fully break down.
Viewed from an international perspective the problem is similar. Lightweight plastic grocery bags are said to be particularly harmful due to their propensity to be carried on a breeze and become attached to tree branches, fill roadside ditches or end up in public waterways, rivers or oceans. In one instance, Cape Town, South Africa, had more than 3000 plastic grocery bags that covered each kilometre of road. In this century, an estimated 46,000 pieces of plastic have been estimated to be floating in every square kilometre of ocean worldwide.
Critics of plastic bag use in Australia claim that this country should not be contributing to this global problem.
6. Biodegradable plastic bags are not a solution to the plastic bag disposal problem
Most supermarkets use a plastic that is at least partly degradable - either photodegradable or biodegradable. But controversy exists as to whether these advances help solve the problem or make it worse.
Photodegradable plastic will degrade only in the presence of sunlight, but in many cases the bags end up buried in a landfill. Being photodegradable does make sense for those bags that wind up as litter along our highways. But the possibility exists that increased litter could be the actual result if people believe that degradable plastic will simply disappear.
Biodegradable plastics are intended to decompose in landfills because of the presence of fungi, bacteria, and moisture. But the American Western Corporation has stated that decomposition does not occur rapidly in landfills, due to the scarcity of enzymes that would catalyse the process.
There are many environmentalists who are concerned that the decomposition products of degradable plastic bags are also a problem. John Ruston, an economics analyst with the Environmental Defence Fund (EDF), has stated that degradable plastics degrade into dust, which is still plastic.
Degradable plastics are also seen as contaminants when it comes to recycling. Experts say that when the degradable version is mixed with regular plastic, it can pollute the plastic resin, which is the substance that is recycled.
The federal Environment Minister, Peter Garrett, has stated that biodegradable plastic bags were not the answer, with some taking as long as 1000 years to break down. He has also acknowledged composting and other environmentally friendly waste options were not viable in every home, particularly densely populated urban areas.