We Have Breached The Safe Planetary Limit For Synthetic Chemicals, Scientists Warn

From sea to land to sky, Earth's systems are contaminated with synthetic substances, and scientists warn it has already pushed the integrity of our planet over the brink.

Today, there are about 350,000 human-made chemicals on the market, including plastics, pesticides, industrial chemicals, cosmetic chemicals, antibiotics, and other drugs.

The fact this number continues to rise at an extraordinary rate makes it virtually impossible for any authority to keep track of their potential impacts on the environment.

At this point, there's no keeping up. Now, a new analysis of the situation suggests we have firmly crossed a planetary boundary into an unsafe space.

Since the 1950s, chemical production has increased by 50-fold. By 2050, it's on track to triple again.

"The rate at which these pollutants are appearing in the environment far exceeds the capacity of governments to assess global and regional risks, let alone control any potential problems," says ecotoxicologist Bethanie Carney Almroth from the University of Gothenburg.

Even if we can slow chemical production in the future, novel entities of our own making have already infiltrated the atmosphere, the hydrosphere, the cryosphere, the geosphere, and the biosphere.

Given that many of these chemicals can live 'forever' in the environment, any potential threat they pose could be the foundation for ongoing problems far into the future.

Ignoring the problem is foolish, but that is largely what humanity has done.

In 2009, an international team of researchers put together a list of nine boundaries that kept our planet stable for human existence, including greenhouse gas emissions, the ozone layer, forests, and freshwater.

In 2015, they concluded humanity had breached four of these boundaries: climate change, greenhouse gas emissions, land-system change, and the extinction rate.

Until now, chemical pollution, or 'novel entities', had never been quantified.

Like a cap on greenhouse gases, researchers say nations also need to limit the rapid production of synthetic chemicals, while assessing the ones they've already got.

Today, tens of thousands of chemicals on the market are untested, and even the ones that have been assessed for health and safety still hold many unknown risks.

While some chemicals might be safe on their own, for instance, studies have shown they can grow toxic when breaking down or in the presence of other chemicals. If enough of these byproducts accumulate in the environment, it could potentially have long-lasting and detrimental impacts.

Much of the research so far has focused on the impact of chemicals on human health, but our species can't live without the environment around us. 

Entities like the US Food and Drug Administration are required to assess the environmental impact of new pharmaceuticals for approval, though in spite of the best intentions, it can often take time for more subtle influences to become apparent.

The chemicals in some sunscreens, for instance, have turned out to be toxic to coral. In recent years, antidepressants have also been found accumulating in water sources, where they appear to impact how some fish hunt for food.

Avoiding similar mistakes in the future will be all but impossible if we do not dramatically slow the global production of novel entities, and soon.

"Shifting to a circular economy is really important," says Sarah Cornell, who works in sustainability research at the Stockholm Resilience Centre in Sweden.

"That means changing materials and products so they can be reused not wasted, designing chemicals and products for recycling, and much better screening of chemicals for their safety and sustainability along their whole impact pathway in the Earth system."

It's a gargantuan task, but so are the consequences.

The study was published in Environmental Science & Technology.

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