Plastics are currently an integral part of everyday life. They are found in mobile phone cases, PET bottles and of course in the ubiquitous plastic bag. The petroleum-derived materials release carbon dioxide during decomposition, which then contributes to global warming. About 400 million tons of CO2 are released year after year due to the decomposition of plastic. Researchers estimate that in 2015, up to 15 percent of CO2 emissions could be attributed to plastic products. So-called bioplastics should counteract this. But even this plastic alternative is much less environmentally friendly than expected, as researchers from the University of Bonn found.
Bioplastics should reduce CO2 emissions
Instead of crude oil, bioplastics use renewable raw materials such as may, wheat or sugarcane as raw materials for production. These plants extract CO2 from the air for their growth and thus compensate for the CO2 emissions that later arise from the decomposition of the plastics. Under the line so a zero-sum game, you should think. Whether this is really the case, researchers around Neus Escobar from the University of Bonn have now investigated – and have come to interesting results. “ The production of large quantities of bioplastic changes land use. In global terms, for example, forest areas could be increasingly turned into farmland. But forests bind much more carbon dioxide than corn or sugar cane, if only because of their larger biomass, „says Escobar.
In the past, the example of biofuels has already shown that it is not just a theoretical effect. Increased demand led to massive deforestation of environmentally friendly fuels in some countries. Escobar and his team now wanted to know how an increased use of bioplastics would impact.
The researchers examined two scenarios
To this end, the researchers have used a computer model that maps the entire world economy and has already been used to study the effects of increased biofuel demand. “ We have assumed that the bioplastics share of major producers – Europe, China, Brazil and the US – will increase to five percent. In doing so, we went through two different scenarios: a tax on conventional plastics versus a subsidy for bioplastics“, Says Escobar. In the case of a tax, the demand for ordinary plastics dropped significantly, which was caused by the higher cost of taxation. Every year, CO2 emissions from plastic were reduced by 0.08 percent. Partly, this was because the tax slowed overall economic growth.
At the same time, however, the area used for agriculture increased and the forest area decreased by 0.17 percent, which released large quantities of greenhouse gases into the atmosphere. “ It’s just a one-off effect,“ says Escobar. „Nevertheless, according to our calculations, it takes more than 20 years until it is made up for by the savings achieved, “ continues Escobar.
If bioplastics were subsidized, the demand for conventional plastics would decrease less. However, the impact on the economy as a whole would be lower. But even in this scenario, it would take 20 years for the change to pay off.
Bioplastic hardly protects the climate
“ An increased use of bioplastics from crops does not seem to be an efficient strategy to conserve the climate. But that would probably look different if, for example, vegetable waste were used to produce it. We therefore recommend concentrating the research efforts on this second-generation bioplastic and making it ready for the market, „concludes Escobar.
The researchers also dampened the hope that the increased use of bioplastics will reduce pollution of the oceans, as these types of plastics are not necessarily more readily degradable than petroleum-based plastics. However, bioplastics must be credited with protecting the fossil fuel sources as they rely on other raw materials.
