While Jean-Michel Blanquer was controversial with his vacation in Ibiza, a completely different, much more serious scandal took place last week, without however making as many waves. Scientists from
Stockholm Resilience Center (SRC) assured in a study published on January 18 in the scientific journal Environmental Science and Technology, that the limit “introduction of new entities into the biosphere” had been crossed. We explain why this information, a little vague at first, should have worried the world at least as much as the possible invasion of the Russians in Ukraine.
What is this planetary boundary thing?
In 2009, a group of international scientists created a concept to measure the impact of different factors on the stability of the Earth system. This is represented by the fairly simple image of a pie chart divided into nine categories. Among them, “global warming”, “ozone reduction”, “use of fresh water” or “extinction rate”. Experts have applied themselves to measuring up to what level humanity can continue to develop and prosper. One of these categories has crossed, according to their calculations, the limit beyond which this equilibrium is no longer possible: this is the limit “introduction of new entities into the biosphere”, which can also be call the limit “chemical pollution”.
This is big and bad news. The planetary boundary for chemical pollution (aka ‘novel entities’) has been quantified for the first time – and it’s now clear that humanity is massively transgressing levels that are safe for life on Earth. Plastics! Read on. https://t.co/OEHWdSOX23 pic.twitter.com/lAwgRG0y3G
— Kate Raworth (@KateRaworth) January 18, 2022
What is hidden behind so-called “chemical pollutants”?
On paper, chemical pollution corresponds to all the entities emitted during releases of chemical products of industrial and/or domestic origin. “This pollution can result, for example, from the use of pesticides, detergents or even heavy metals, explains Mélanie Mignot, lecturer at the CNRS-COBRA laboratory in Rouen. It can also be generated during occasional accidents. In the latter case, it is for example industrial accidents or oil spills. Finally, and obviously, there are plastics which “generate pollution for fauna and flora when they are released into the environment”, continues the expert.
If the definition of chemical pollutants is simple, listing them is much less so. According to figures from the Stockholm Resilience Center, there are around 350,000 different types of manufactured chemicals on the market today. “This ranges from plastic bags to molecules,” explains Fabienne Lagarde, researcher from the University of Le Mans in the CNRS joint research unit. The concept of “new identities” has the advantage of bringing them all together under the same banner: “Substances which were not naturally present in the environment before the last century for the vast majority”, summarizes she.
Why is this limit crossed today?
“For a very long time, scientists and specialists believed in the capacity for resilience. Namely that the marine environment was capable of absorbing pollutants”, explains François Galgani, oceanographer at the French Research Institute for the Exploitation of the Sea (Ifremer) and specialist in plastics. Except that today, the report is without appeal. “Some areas are considered dead: there have been too many imbalances, the ecosystem has been too disturbed. »
The SRC study shows that the production of these new entities has multiplied by 50 in 70 years and that it will triple again by 2050. With such mass production, the curve of substances that end up in the environment can only be exponential. “We are at densities that exceed one million items of waste per square kilometer in certain areas at the bottom of the Mediterranean. We are at 24,000 billion floating particles on the surface of the oceans”, chooses to give as figures (among many other equally depressing) François Galgani. In 2015, when we were already questioning him on the subject, the oceanographer spoke only of 5,000 billion.
Latest observation for the expert, if the quantities of plastic waste are fairly homogeneous in the areas where they are produced, they increase in remote regions, such as the polar environments where there is however no population, nor ‘industry. “In the areas where this waste is produced, we reach plateaus, but as it accumulates, it overflows and the currents bring it little by little to these remote areas”, explains François Galgani.
Should we be worried?
No need to prolong the suspense, the specialists are unanimous, the answer is “yes” and for different reasons. “The rate at which societies produce and release new chemicals and other new entities into the environment is not compatible with remaining in a safe operating space for humanity,” says the co-author of the Patricia Villarubia-Gómez study. “These pollutants can accumulate in the environment and/or form degradation by-products that can pose a risk to human health and the environment”, analyzes Mélanie Mignot, whose research focuses on these chemical pollutants. This accumulation poses a problem, because even if a product is prohibited, as is the case for certain pesticides or additives, they can still remain present for a long time.
In nature, “the concern is to know if the environment is irreversibly altered and if not, how long it can take to regenerate”, explains François Galgani, emphasizing that the answer is variable “depending on the pollutant and whether its a one-off or permanent contribution”. In some cases, the answer is unfortunately already known. “We are not going to fetch the millions of tonnes of undegraded plastics from the bottom of the oceans. It requires too much money and energy”, launches, pragmatically, Fabienne Lagarde. As for substances that degrade, some become unrecoverable, such as microplastics. “You can’t comb through all the oceans on the planet,” she adds.
Why do we talk about it less than global warming?
According to the pie chart of the SRC scientists, the limit concerning the “introduction of new entities into the biosphere” is much more exceeded than that linked to climate change. According to François Galgani, if we talk less about it, it is above all a matter of sensitivity, because chemical pollution is local while climate change is global. “The problem of pesticides in Martinique is regional and anyone who lives in Switzerland doesn’t care. If there is an increase in temperature, all the ecosystems are affected”, gives the example of the oceanographer.
Chemical pollution is also more complicated to measure. As chemical pollutants belong to very diverse families, the message is more “diffuse or rough”, notes Fabienne Lagarde. “For the climate, we have a well-identified responsible: greenhouse gases and a measurable indicator: +1 or +2 degrees on temperatures”, she analyzes. It’s not just for the general public that it’s complex. “Contaminants, once in the ecosystem, can undergo degradation processes,” explains Mélanie Mignot. These new molecules which “are not necessarily known” are at lower concentrations. Although they are no less harmful, they “require sensitive instruments to detect them at low thresholds”, continues the expert, whose laboratory is precisely developing methods for analyzing complex samples from the environment to better understand the transfer of pollutants in the ecosystem.
For Fabienne Lagarde, one of the solutions to no longer go beyond this border would obviously be to cut off the tap of mass production. “Innovation can no longer just be the creation of a new molecule or substance, we now have to think in cycles. »