Wednesday, May 18

Environment. Chemical pollution: what is this “fifth limit” that our planet has exceeded?

In 2009, the Stockholm Resilience Center introduced for the first time the notion of “planetary boundaries” in scientific discourse. This term, now adopted by the United Nations and many scientific institutions, is used to define the thresholds that humanity must not exceed if it wants to continue to live in a safe ecosystem. If these limits are crossed, Man exposes himself and his environment to sudden and potentially catastrophic changes.

Bad news: a few days ago, a study published in the scientific journal Environmental Science and Technology concluded that humanity had crossed one of these limits: that of chemical pollution. Explanations.

Five out of nine limits already exceeded

The Stockholm Resilience Center has defined nine planetary limits, the overstepping of which poses a serious threat to the balance of our ecosystems. These are climate change, the integrity of the biosphere, the disruption of the biochemical cycles of nitrogen and phosphorus, the change in land use, the introduction of new entities into the environment ( i.e. chemicals), the use of fresh water, the depletion of the ozone layer, the acidification of the oceans and the concentration of atmospheric aerosols.

These boundaries have remained relatively stable since the beginnings of human civilizations 10,000 years ago. But in recent decades, out of these nine limits, five have been reached, or even largely exceeded for some: climate change, erosion of biodiversity, disruption of nitrogen and phosphorus cycles, modification of the use soils and therefore, more recently, chemical pollution.

What is the chemical release limit?

In the study published on January 18, a team of 14 scientists quantified for the first time the impact of pollution from synthetic chemicals and “new entities” released into the environment. Their results enabled them to conclude that chemical pollution has therefore exceeded the sustainable limit that our ecosystems can withstand without fear of consequences.

Currently, there are 350,000 different types of chemicals in the world. These can obviously be plastics, but also textiles, medicines, industrial chemical compounds… So many products created by human activity and whose “effects on the planetary system are still largely unknown”, explains the CBC.

If they are not all individually dangerous, it is the cocktail of 350,000 chemicals of all kinds that poses a heavy threat to the environment.

“Since 1950, the production of chemicals has increased 50 times the world. And it should triple again by 2050,” warns Patricia Villarubia-Gómez, member of the Stockholm Resilience Center and co-author of the study. Plastic production alone even increased by 79% from 2000 to 2015.

A multiplication that poses a heavy threat

“The rate at which these pollutants appear in the environment far exceeds the ability of governments to understand their global and regional risks, and therefore to control the problems that will arise from them,” adds Bethanie Carney Almroth, also author of the study.

The rate at which our societies are producing and releasing new chemicals and entities into the environment is not compatible with the safe development of humanity.

Patricia Villarubia-Gomez

Indeed: these products will not disappear in the snap of a finger. Today, the total mass of plastics on the planet is twice that of all mammals combined. In addition, 80% of the plastics produced remain in the environment. “Some of these pollutants are found everywhere, from the Arctic to the Antarctic,” laments Bethanie Carney Almroth. Bad news, then the presence of these plastics and other toxic products in the four corners of the globe directly threatens the proper functioning of ecosystems, whether soils, forests, oceans.

Living organisms are also directly affected by the toxicity of these products.

Once a limit is crossed, it is difficult to go back

What to do, then, in the face of these 350,000 types of chemical products dispersed throughout the world, from the bottom of the oceans to Mount Everest? “The transition to a circular economy is very important,” says the Stockholm Resilience Center. “This means opting for reusable products and materials, making other chemicals made to be recycled, and better assessing the health and environmental risks and impact of these products,” the scientists continued in their statement.

Especially since the nine limits of the Earth influence each other. In other words, crossing one boundary, such as the release of chemicals into the environment, can aggravate the degradation of another, such as biodiversity loss or climate change.

Be that as it may, “if you cross a ‘planetary limit, you can’t go back,’ explains to franceinfo Natacha Fondran, engineer and professor in environmental assessment. The only thing to do is “to adapt” to limit the consequences and risks of runaway and therefore the impact of the destabilization of these limits on ecosystems and human health.

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