Bioplastics are often marketed as an environmentally and climate-friendly alternative to conventional petroleum-based plastics. However, an analysis by the University of Bonn now suggests that a switch to plant-based plastics could have a less positive effect than expected. For example, increasing use of bioplastics is likely to increase global greenhouse gas emissions. The study was published in the „Environmental Research Letters“. We have spoken to Dr. Neus Escobar at University of Bonn. 

NAYA: Dear Dr. Neus Escobar many thanks for taking the time. Could you please provide us a brief overview of Plastic and Bioplastic and what is the difference?

Dr. Neus Escobar: Of course. Plastic is usually made from petroleum. This has negative consequences for the global climate: the carbon dioxide contained in them is released when they are broken down and thus contributes to global warming. Around 400 million tons of CO2 are released into the atmosphere worldwide every year – half as much as Germany blew up in 2017. In 2050, plastics could already be responsible for 15 percent of global CO2 production.

Bioplastics, on the other hand, is almost climate neutral because it is based on renewable raw materials such as corn, wheat or sugar cane. For their growth, these plants need carbon dioxide, which they take from the air. The production of bioplastics therefore uses CO2, just as much as will be released later when it is burned or decomposed. Overall, their greenhouse gas balance is therefore balanced. Bioplastics are therefore often marketed as an environmentally friendly alternative. Bio in the word Bioplastic is not an indication of organic it only refers to the subject that it is based on plants.

NAYA: Thank you! So what makes bioplastic different from plastic?

Dr. Neus Escobar: The production of large amounts of bioplastic changes land use. From a global perspective, this could, for example, increasingly transform forest areas into agricultural land. However, forests bind significantly more carbon dioxide than maize or sugar cane, if only because of their larger biomass. In addition, older trees can filter much larger quantities of CO2 than young trees. Experience with biofuels shows that this effect is not theoretical speculation. The increasing demand for the „green“ energy source has resulted in massive deforestation in some countries. I have simulated the effects of an increased use of bioplastics with colleagues. To do this, we used and expanded a computer model that had already been used to calculate the biofuel effects. It is based on a database that maps the entire global economy.

NAYA: Could you tell us more about this research you conducted with your colleagues?

Dr Neus Escobar: For our model, we made the assumption that the share of bioplastics among the most important producers – Europe, China, Brazil and the USA – rose to five percent. We went through two different scenarios: a tax on conventional plastics versus a subsidy for bioplastics. The most dramatic were the effects in the tax scenario: Since this made conventionally manufactured plastics significantly more expensive, the demand for them fell significantly. Worldwide, 0.08 percent fewer greenhouse gases were emitted each year. However, part of this decline is due to economic turmoil, as the overall tax slowed economic growth. At the same time, the agricultural area increased in this scenario, while the forest area decreased by 0.17 percent. As a result, enormous amounts of greenhouse gases were released into the atmosphere. This is only a one-off effect. Nevertheless, according to our calculations, it will take more than 20 years for it to be offset by the savings achieved.

Overall, it takes a lot of energy for the switch to bioplastic to pay off. In addition, the researchers estimate the cost of this strategy to be more than $ 2,000 per tonne of greenhouse gases – a comparatively high sum. A subsidy for bioplastics would have clearly different effects in many respects. The compensation time of a good 20 years and the costs for the greenhouse gas reduction would change little here, too.

NAYA: Would you see the change from bioplastic to plastic an effective change with positive impact?

Dr Neus Escobar: Increased use of bioplastics from crop plants does not seem to be an efficient strategy to protect the climate. Especially since it would have a number of other negative effects, such as rising food prices. But that would probably be different if, for example, vegetable waste was used in the production. We recommend concentrating research efforts on this second generation bioplastic and bringing it to market maturity. The hope that the pollution of the world’s oceans will decrease through bioplastics does not necessarily have to be fulfilled. Plastic from plants is not automatically more easily degradable than petroleum. Bio-PE and bio-PET rot is just as badly as their petroleum-based counterparts. In addition bioplastic takes land away for other food sources and / or drives deforestation. However, bioplastic has one advantage: it protects the increasingly scarce fossil fuel sources. Our team basically came to the conclusion that those who want to protect the environment, should rather use a different strategy. It makes more sense to use plastic sparingly and to recycle as much as possible and where ever possible.

NAYA: Many thanks for taking the time for speaking with us Dr. Neus Escobar.

Read more about Dr Neus Escobar’s and his colleagues research  here using the link below:

Neus Escobar, Salwa Haddad, Jan Börner und Wolfgang Britz (2018), „Land use mediated GHG emissions and spillovers from increased consumption of bioplastic“; Environmental Research Letters;  https://doi.org/10.1088/1748-9326/aaeafb

We have also consolidated a long reading list with further information about this topic.


Reading List 

Learn more about what bioplastic is and does to make your own informed decision on this topic.

Deutsche Artikel: 

WWF DE – Available on: https://mobil.wwf.de/themen-projekte/meere-kuesten/plastik/unsere-ozeane-versinken-im-plastikmuell/https://www.wwf.ch/de/unsere-ziele/verschmutzung-der-meerehttps://www.vontobel.com/de-ch/impact/sie-moechten-verhindern-dass-plastik-die-ozeane-verschmutzt/

National Geographic DE – Available on: https://m.geo.de/natur/nachhaltigkeit/16466-rtkl-vermuellte-ozeane-woher-stammt-der-plastikmuell-im-meerhttps://www.google.co.uk/amp/s/www.manager-magazin.de/unternehmen/industrie/plastik-fuenf-grafiken-zum-problem-mit-muell-aus-kunststoff-a-1206656-amp.html

Manager Magazin DE – Available on: https://www.google.co.uk/amp/s/www.manager-magazin.de/unternehmen/industrie/plastik-fuenf-grafiken-zum-problem-mit-muell-aus-kunststoff-a-1206656-amp.htmlhttps://ourworldindata.org/plastic-pollution

Zeit DE – Available on: https://www.google.co.uk/amp/s/www.zeit.de/amp/politik/ausland/2020-01/plastikverbot-eu-kommission-umweltschutz-virginijus-sinkevicius

Merkur DE – Available on: https://www.google.co.uk/amp/s/www.merkur.de/politik/initiative-gegen-mikroplastik-wo-uns-grossbritannien-italien-und-schweden-voraus-sind-zr-10359610.amp.html

AMP DW DE – Available on: https://www.google.co.uk/amp/s/amp.dw.com/de/ist-bioplastik-die-l%25C3%25B6sung-gegen-umweltverschmutzung-und-klimawandel/a-46171840

Nachhaltiger Warenkorb – Available on: https://www.nachhaltiger-warenkorb.de/was-steckt-hinter-dem-begriff-bioplastik/

Welt DE – Available on: https://www.google.co.uk/amp/s/amp.welt.de/wissenschaft/article173614365/Plastikmuell-Abbaubaren-Kunststoffe-sind-die-Loesung.html

Bund DE – Available on: https://www.bund.net/themen/chemie/achtung-plastik/alternative-bioplastik/

Fauenhof DE – Available on: https://www.umsicht.fraunhofer.de/de/ueber-fraunhofer-umsicht/nachhaltigkeit/nationale-informationsstelle-nachhaltige-kunststoffe/polymere-kunststoff/biokunststoffe.html#tabpanel-1

Verbraucherservice Bayern DE – Available on: https://www.verbraucherservice-bayern.de/themen/umwelt/wie-nachhaltig-ist-bio-plastikhttps://www.global2000.at/bioplastikhttps://youtu.be/HUYMHEqepyc

English Articles: 

National Geographic UK – Available on: https://www.google.co.uk/amp/s/www.nationalgeographic.de/planet-or-plastic/2018/11/bioplastik-nachhaltige-zukunft-oder-greenwashing-luege/amp

Euronews UK – Available on: https://www.google.co.uk/amp/s/www.euronews.com/living/amp/2019/11/16/who-are-the-world-s-top-ten-marine-plastic-polluters

Read also our other blog on this topic which you can find here with additional resources: