New study says the world has passed its ‘carrying capacity’ for man-made chemicals and plastics
By Molly Taft
Humans have produced so many chemicals and environmental pollutants that we’re currently exceeding the limits of a “safe operating space for humanity,” a new study finds. That could mean that the planet, as well as our health and wellbeing, is in serious jeopardy.
The study, published Tuesday in Science and Technology, illustrates just how much manmade stuff we’re dumping into the environment. Chemical production, the study found, has increased worldwide by 50 times since 1950; if current trends continue, production will increase another 50% by 2050. Plastic production alone has shot up by a whopping 79% between 2000 and 2015, despite conservation and recycling efforts.
“We are harming the entire planet, including ourselves, and challenging the stability of the Earth in such a way that it could threaten our own ability to thrive,” Bethanie Carney Almroth, a professor of biological and environmental sciences at the University of Gothenburg and one of a team of 14 international researchers who contributed to the study, said in an email.
The study is based on the idea of “planetary boundaries,” a framework first proposed by researchers in 2009, that divides the stability of Earth’s existence for the past 10,000 years into nine categories, including climate change, ocean acidification, and the ozone layer. Crossing specific thresholds in each of these areas, this framework posits, threatens the stability of the planet. This study set out to calculate the boundaries for what are known as “novel entities,” or the more than 350,000 manmade chemicals registered on the global market, ranging from plastics to antibiotics to pesticides.
Defining these kinds of boundaries for something that doesn’t occur in nature is a little tricky — how are we supposed to know there’s too much of something on Earth that didn’t exist before humans came along? It’s even more difficult to calculate because very few of the hundreds of thousands of plastic compounds in existence today have been thoroughly studied. The studies that do exist tend to look at hyper-local impacts—not impacts to our whole planet.
To create a robust framework, the study’s authors used what’s called a “weight of evidence” approach that looks at what we know and don’t know about extraction, production, and disposal of chemicals. The approach also considers how quickly we are producing chemicals in large quantities, and its implications for the biosphere. Almroth, whose own research focuses on exposure to chemicals and plastics in aquatic organisms, said this is where the strength of the study’s cross-disciplinary team came into play. “Our combined knowledge and experiences added weight to the conclusions we found ourselves coming to, based on our chosen methodology,” she said.
Using this method, the evidence shows “we have produced (and will to continue to produce, in even increasing volumes) enough toxic chemicals and plastics to disrupt the Earth’s balance,” Almroth said. “We risk destabilizing [the] function of the planet and the safe operating space for humanity.”
The local impacts of plastic alone tell a story of the damages they do to ecosystems and our health. In the past month alone, we’ve learned of elephants dropping dead with stomachs full of plastic and the connection between plastic and IBD. These are small slivers of the greater problem the new research chronicles.
Humanity has found a way to get some forms of pollution under control, including scaling back the production of chemicals that were harming the ozone layer. (To be clear, though, it’s still a work in progress.) But the sheer volume of chemicals being produced is more than enough for concern.
As the study points out, plastics—which are comprised of thousands of different chemicals, making their degradation especially concerning—remain on the planet basically forever: 80% of the plastic produced throughout history is still in the environment. The plastic produced to date outweighs the mass of all mammals on Earth by a two-to-one ratio. Given how quickly plastic production is expected to ramp up in the coming decades, that mass—and the fallout from having so many chemicals in the environment—is only set to increase unless the world makes big, systemic shifts. Those include shifting away from single-use items and winding down fossil fuel production driving the plastic boom.
“This is a dire message, but we are calling for action (rather than apathy or fear),” Almorth said. “We need to find the support and momentum to drive drastic changes.”