The European Commission has pointed out that it would actually be deceptive to describe most types of compostable plastics as “biodegradable” because they will readily biodegrade only in the special conditions found in industrial composting. In the United Arab Emirates they have made it compulsory to use oxo-biodegradable plastic for a range of plastic products, because they know they will never be able to collect all the plastic waste from their deserts and coastline. The law applies to plastic products which are commercially imported as well as those that are made in the UAE. They rejected compostable plastics, because they have to be collected and taken to a composting factory, and do not therefore address the problem of plastic waste in the environment which cannot realistically be collected.
Oxo-biodegradable plastic can be set at manufacture to degrade in whatever approximate timescale is desired, from a few months to a few years after being taken out of its box and given to consumers. If sent to landfill, oxo-degradation cannot continue in the absence of oxygen, and undegraded material will not therefore emit methane.
Like normal plastic, oxo-biodegradable plastic is made from oil, but oil is not imported to make plastic. It is imported for fuel, and plastic is made from a by-product which used to be wasted. It does not therefore increase the amount of oil extracted, and could in fact reduce it. This is because plastic has the same calorific value as the oil from which it was made. It should not be wasted by being sent to landfill, but should instead be sent to modern incinerators, where the calorific value can be captured and used to generate electricity without harmful emissions.
In some countries there is legislation requiring plastic bags to be made of much thicker plastic, but this will not solve the problem. Thicker plastic may be more attractive to waste-collectors, but the thicker the plastic the longer it will last if it gets into the open environment, as some of it surely will. Thick plastic products should therefore also be required to be oxo-biodegradable, but they can still be recycled if collected during their useful life.
Legislation to require plastic products to be oxo-biodegradable should not focus just on shopping bags, but should apply to all short-life plastic products likely to find their way into the open environment.
Oxo-biodegradable plastics are no more a solution to the litter problem than catalytic converters are a solution to air pollution, but both technologies have a role to play. Awareness, education, the enforcement of suitable laws and sound waste management practices should of course be encouraged, but it is unrealistic to think that there will in the foreseeable future be no plastic waste at all in the environment anywhere in the world. The problem cannot be solved by calling it a behavioural issue, nor by making the obvious point that litter is not an authorised disposal route. It is often said that that people would dispose more carelessly of biodegradable plastics, and this is an argument which would if true apply to hydro-biodegradable ("compostable") as well as oxo-biodegradable, plastics.