BIOPLASTICS have been hailed by some as a solution to the plastic problem [1,3]. They look and feel similar to conventional plastic, but are made from renewable resources, such as corn starch, instead of oil . In theory they have two advantages: rapid breakdown, and a low carbon footprint [1,2]. Is this true?
Do they DEGRADE? Sometimes, and not that quickly. In theory, bioplastics should degrade into natural materials which do not pollute the environment . However, they often last for years in soil or seawater [4,9,10], or leave toxic chemicals behind . Some break down in industrial composting facilities, but not in garden compost heaps or landfill .
What about their CARBON FOOTPRINT? Bioplastics can have a lower carbon footprint than most plastic [8,16] because they are made from plants: the plants took in CO2 from the atmosphere through photosynthesis, which is then released again when the bioplastic breaks down [12,17]. While this is carbon neutral, there are some CO2 emissions production process to make bioplastics .
The plants grown to make bioplastic take up farmland that could be used to grow food ; this can result in deforestation to grow more crops [16,18], causing release of CO2 from forests . One study showed that replacing all plastic with bioplastic would take up to 219 million hectares of land (61% of all free arable land) . Luckily, not all bioplastic requires extra land, such as that made from farm waste [13,14].
Another alternative is BIODEGRADABLE plastics, which (like plastic) are made from oil . They are very different from bioplastic, despite the similar name! They are not really any better than normal plastic [6,7]. They degrade faster, but not into natural materials, and produce just as much methane in landfills [3,15].
In the future we will likely have much more planet-friendly plastics [10,11,5]. However, for now, using the popular alternatives is no excuse for wastefulnes . Perhaps the problem is not plastic, but our wasteful use and careless disposal of it.
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