“Would Using Biodegradable Plastics Solve the World’s Plastic Problems?” (OneSharedEarth, 2018) summarises the different alternative plastics (biodegradable, bio-based, etc.) available.
As many of these are derived from fossil fuels, those will have the same impact as conventional plastics on climate change, summarised in “How Does Plastic Affect Climate Change?” (OneSharedEarth, 2020).
Bio-based plastics not derived from fossil fuels are essentially produced from food crops such as maize, wheat or sugar cane. These plants get the carbon dioxide (CO2) that they need from the air. Producing these plastics therefore consumes CO2, which compensates for the amount that is later released at end-of-life. Hence, bio-based plastics are in principle climate-neutral. But...
The production of bio-based plastics could potentially lead to an increase in the conversion of forest areas to arable land. However, forests absorb considerably more CO2 than these food crops annually. Experience with biofuels has shown that this effect is not a theoretical speculation. The increasing demand for the “green” energy sources has brought massive deforestation to some countries across the tropics.
Greenhouse gas emissions from
- global land cover changes
- Nitrous oxide (N2O) from excessive fertiliser application in agriculture
- methane (CH4) mostly from livestock
- carbon dioxide (CO2) emissions from overall energy consumption during production & disposal, through running of machinery
may imply decades of carbon payback time.
“More Bioplastics Do Not Necessarily Contribute to Climate Change Mitigation” (Universität Bonn, 2018)
Escobar N and others, “Land Use Mediated GHG Emissions and Spillovers from Increased Consumption of Bioplastics” (2018) 13 Environmental Research Letters 125005