Why chemicals and plastics pose a risk to our future
Humanity has released and spread numerous new substances into the environment. Since they were rarely or never involved in evolutionary processes, organisms have not been able to develop strategies to cope with these xenobiotics. These foreign substances can be poisonous, persistent, highly mobile and can affect our health and the Earth system.
It is estimated that there are 350,000 chemicals on the global market, ranging from solvents and pesticides to medicines. Plastics, which are artificial materials made of synthetic polymers, are also produced in chemical processes and contain plasticizers, dyes and flame retardants. Some of these substances that humanity has introduced into the environment can have an impact on the health of humans and other living beings, for example because they can cause cancer or have the potential to disturb the hormone system.
In the planetary boundaries concept, chemicals and plastics are counted among the substances that are foreign to nature and the Earth system, substances to which living things have been unable to adapt through evolution. These substances, which are part of a collective category called “novel entities” that also includes radioactive waste, heavy metals and rare earths, have only become widely distributed in the environment through human activity.
For the developer of the planetary boundaries concept, Johan Rockström, the novel entities are one of the three most critical factors for our future, along with biodiversity loss and climate change.* Researchers determined in 2022 that the planetary boundary for novel entities has already been exceeded for chemicals and plastics and that humanity is now living outside safe limits.
Diversity and quantity of chemicals makes them uncontrollable
Chemical production worldwide has increased 50-fold since 1950. The production of plastics rose nearly 80 percent from 2000 to 2015. Strong growth in the market for plastics and chemicals is expected to continue in the years ahead, even as the weight of all the plastic on Earth already exceeds that of all animals on land and in the oceans combined.
Large amounts of plastics and chemicals are being released – usually unintentionally or due to poor management – into the environment. An estimated 79 percent of the plastic produced since 1950 is now either in landfills or in oceans, rivers, lakes, soil and the air.
How can we get back to the safe zone?
In order to return levels of foreign substances to the safe side of the planetary boundary as soon as possible, their release into the environment must be drastically reduced: for example, by reducing the amount of waste and by safely expanding the circular economy. It may be necessary to phase out especially troublesome substances and switch to alternatives, or to set production limits.
With so many new substances being produced and released into the environment, it is practically impossible to understand, much less control, the risks for people, ecosystems and the Earth system as a whole, according to the researchers who recently declared that the planetary boundary had been exceeded.
Chemical cocktails and polluted rainwater
Toys, packaging, clothing and other products usually contain a mixture of various chemicals. For example, plastics are mixed with some 10,000 chemicals to influence their resistance to sunlight and numerous other characteristics. The result is a diverse “cocktail” of chemicals whose impact on our health has hardly been investigated – and hardly can be given the number of possible combinations. Due to trade secrets, the manufacturers of these chemicals rarely reveal their “recipes.” Often even they are not fully aware of the chemical composition. This is because some substances, the so-called NIAS (non-intentionally added substances), are not even added intentionally, yet they too are relevant to assessments of the environmental impact.
Scientists have detected one group of long-lived substances called per- and polyfluoroalkyl substances (PFAS, PFOS or PFC) in rainwater worldwide, even in remote regions such as the Antarctic and the Tibetan Plateau. They measured concentrations of these “forever chemicals” that were 14 times as high as the levels recommended by the US Environmental Protection Agency (EPA). The EPA had lowered the limit because these chemicals might also affect children’s reactions to vaccines. Such substances can also accumulate in the human body and, according to further studies, may affect child development, fertility, obesity, cancer risk and cholesterol levels. When limits are exceeded, the rainwater is no longer suitable for drinking. Here too, the planetary boundary has been exceeded.
How chemicals and plastics affect the climate
The production of large amounts of chemicals and plastics also has significant consequences for the climate. Plastic production and disposal alone cause approximately 4.5 percent of the world’s greenhouse gas emissions and could consume 10 to 13 percent of the carbon dioxide budget remaining through 2050 for achieving the climate targets of the Paris Agreement. Pollution by microplastics and chemicals could also be detrimental to other processes that are important for the climate. For example, it is suspected that dark microplastics could change the amount of sunlight reflected back into space by snow and ice. Or particles in water could reduce its transparency, causing algae to absorb less carbon dioxide from the air and reducing their ability to counter climate change.
Scientific editing: Ralf Ebinghaus, Helmholtz-Zentrum Hereon, Melanie Bergmann, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research.
* Interview with Johan Rockström on Living on Earth (2016).
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Updated December 9, 2022.