Bioplastics — often promoted as a climate-friendly alternative to petroleum-based plastics — may lead to an increase in greenhouse gas emissions, according to a study.
The study from the University of Bonn in Germany, published in the journal Environmental Research Letters, suggests that shifting to plant-based plastics could have less positive effects than expected.
Bioplastics — often promoted as a climate-friendly alternative to petroleum-based plastics — may lead to an increase in greenhouse gas emissions.
Bioplastics are in principle climate-neutral since they are based on renewable raw materials such as maize, wheat or sugar cane. These plants get the CO2 that they need from the air through their leaves. Producing bioplastics therefore consumes CO2, which compensates for the amount that is later released at end-of-life. Overall, their net greenhouse gas balance is assumed to be zero. Bioplastics are thus often consumed as an environmentally friendly alternative.
However, at least with the current level of technology, this issue is probably not as clear as often assumed. This is because the production of bioplastics in large amounts would change land use globally. This could potentially lead to an increase in the conversion of forest areas to arable land. However, forests absorb considerably more CO2 than maize or sugar cane annually, if only because of their larger biomass.
Concerns over the increased use of plastics:
Plastics are usually made from petroleum, with the associated impacts in terms of fossil fuel depletion but also climate change. The carbon embodied in fossil resources is suddenly released to the atmosphere by degradation or burning, hence contributing to global warming.
This corresponds to about 400 million metric tonnes of CO2 per year worldwide, almost half of the total greenhouse gases that Germany emitted to the atmosphere in 2017. It is estimated that by 2050, plastics could already be responsible for 15% of the global CO2 emissions.
Main advantages of bioplastics:
- They can reduce our carbon footprint.
- Less consumption of non-renewable raw materials.
- A reduction of non-biodegradable waste, which contaminates the environment.
- Increased energy savings in terms of production.
- Fewer harmful additives such as phthalates or bisphenol A.
- No adverse change to flavour or scent in food stored in bioplastic containers.