Where the Rubber Meets the Road
12/7/24 - ubiquity, toxicity, and the road we're on
Hello everyone:
If you missed last week’s cheerful post highlighting some beautiful nature-based linocut art, please check it out.
This week I’m taking a big swing on a heavier topic that isn’t talked about nearly enough. I hope you find it as important as I do.
As always, please remember to scroll past the end of the essay to read this week’s curated Anthropocene news.
Now on to the writing:
So much of what needs to change in this strange, difficult epoch in Earth history has to do with scale. It’s not just human behavior; it’s how much of that behavior is happening. Deforestation and single-use plastics on a small scale are problems, but they’re small problems. Local overfishing doesn’t deplete the oceans. Burning firewood and fields is one thing, but burning tens of millions of years of stored carbon in the last several decades has overwhelmed Earth’s slow-and-steady temperature management system.
When we talk about scale, of course, we’re really talking about population growth and consumption intensity. If we still had a population of one billion (only 220 years ago) or two billion (a mere century ago), or if global per capita consumption was like that of the citizens of Chad, we would not be busting through planetary boundaries like a mob of Black Friday shoppers shattering the glass entrance doors at a Wal-Mart.
The word that always comes to mind when I think about this is ubiquity. It’s fun to say, and adds a bit of gloss to the dark core of the Anthropocene. Perhaps a better way to say it, though, is via a recent movie title: humans and our impacts are “everything everywhere all at once.”
So many of us have the best intentions when it comes to living a more gentle, rational ecological existence. But as I often point out, so much of this Anthropocene life means being trapped between poor choices. And, as any therapist or ethicist might explain, our choices are where the rubber meets the road.
Which leads me to my topic, an example of toxic ubiquity that may not be foremost on your mind. It is, literally, where the rubber meets the road.
Heather and I recently purchased a 2017 Prius V wagon, and we love it. For one thing, we’ve always lived a low-budget artist life and been the kind of folks who buy old used cars and ride their leaky, rusted frames into the ground. This Prius is spiffy and new-ish, and offers great mileage. We love the small reduction in our energy footprint, but of course there’s a deeper analysis to make here.
Modern transportation provides yet another reminder that we can’t shop our way out of the Anthropocene. There’s a lot of discussion about the impacts of hybrids and EVs on emissions (good, mostly) and on resource extraction (ugly in the short term, but good eventually) but we should be paying similar attention to the toxic ubiquity of tires.
We most often think of our cars and trucks by their exterior appearance, or by the upholstered space within the frame where many of us spend hours every day. But each vehicle exists in the living world largely as its extracted materials and its polluting emissions. That’s a) the mining and other industrial processes before it gets to us; b) the toxic noise, exhaust, brake and tire debris, and other pollution while we’re driving it; and c) its material fate once driven into the ground.
Tires tell that whole story all on their own.
The scale: 1.5 billion cars and trucks are on the world’s roads now, predicted to double to 3 billion vehicles by 2050. (Multiply by four to count the tires.) Roughly 3 billion new tires are made each year, while about 800 million are discarded, nearly a third of them - nine tires per second - in the U.S. alone. Up to 75% of discarded tires end up in landfills.
The price of the recipe: The story starts in places like this Cambodian wildlife sanctuary being erased by the spread of a rubber plantation. (Video by Sean Gallagher, borrowed from a harrowing Yale e360 article on the topic.)
Tire manufacturing includes both synthetic rubber (derived from fossil fuels) and natural rubber (harvested from trees). Choosing between them offers a classic Anthropocene trade-off: Synthetics are incredibly toxic but natural rubber production for tires is already a major cause of tropical deforestation in Southeast Asia and Africa.
The global deforestation for rubber is worse than for cocoa or coffee and almost as catastrophic as it is for the production of palm oil. But unlike palm oil, there’s not much public pressure to stop the rubber-related erasure of tropical forests. As one researcher in the Yale article says, “Despite the ubiquity of rubber products, there is a low public awareness that rubber is a crop, let alone a crop that drives deforestation.” And another expert asks, “When did you last see deforestation-free rubber tires advertised?”
Here’s more detail on the recipe from another Yale e360 article. The recipe includes lead, which seems crazy, considering how much has been done in my lifetime to remove lead from gasoline:
Tires are made from about 20 percent natural rubber and 24 percent synthetic rubber, which requires five gallons of petroleum per tire. Hundreds of other ingredients, including steel, fillers, and heavy metals — including copper, cadmium, lead, and zinc — make up the rest, many of them added to enhance performance, improve durability, and reduce the possibility of fires.
All of this toxicity begins in the cooking up of new tires, even before the rubber meets the road. A comprehensive, holistic lifecycle assessment of the environmental impacts of tires notes that production of each tire requires the equivalent of 333,000 kg of CO2. Moreover, the manufacturing process
emits carcinogens and radioactive compounds (e.g. radon-222 and carbon-14), contributes to stratospheric ozone depletion, and requires massive consumption of water and electricity… Combined, the various chemical components and the particles create chemical cocktails of heavy metals (e.g., Zn), natural and synthetic rubber and plastics, hydrocarbons (e.g., PAHs), and traces of other chemicals (e.g., 6PPD) that can have negative effects on human health and the environment.
Multiply all that, each year, by 3 billion.
What tires leave behind: On the road, the largest portion of noise pollution from cars and trucks is the sound of tires gripping the pavement. As Ben Goldfarb writes in Crossings, his truly wonderful and essential book on road ecology, road noise “bleeds into its surroundings, a toxic plume that drifts from its source like sewage.” He goes on to say that
More than 80 percent of the United States lies within a kilometer of a road, a distance at which cars project twenty decibels and trucks and motorcycles around forty, the equivalent of a humming fridge,
and that
road noise isn’t merely an irritant: it’s also a form of habitat loss, a repellent that evicts wild creatures from environments in which they would otherwise thrive.
All of us alive now have grown up in an era increasingly sensitive to tailpipe emissions, but the reality is that tires emit far, far more particulates than exhaust systems. Tires are always shedding microplastics and other particles, adding up to about 6 million tons annually around the world. A remarkable research initiative in the UK found that a car’s four tires emit a trillion ultrafine particles - smaller than 100 nanometers - for every kilometer driven. I’ll say that again: a trillion for every kilometer driven.
That’s 1.61 trillion particles per mile.
Remember that these particles, large and small, are emitted from the toxic recipe of hundreds of chemicals in the tires, and that the smallest of them can go airborne for great distances. Once they find us, and we inhale them, they’re able to pass through lung tissue and the blood/brain barrier.
Far too little research has been done on all these health and environmental impacts, and there’s much we don’t know about the impact of tires on the living world, but as one expert on the topic put it, “We know enough to say that it is possibly the biggest, and possibly the least well understood, environmental problem related to transportation.” Ben Goldfarb put it more succinctly in Crossings: “[We] paved the earth for cars, then used them to poison it.”
One estimate suggests that, globally, 78% of microplastics entering the oceans come from tire wear. From Yale e360:
These fragments are ingested by marine animals — particles have been found in gills and stomachs — and can cause a range of effects, from neurotoxicity to growth retardation and behavioral abnormalities.
The salmon story: While the chemistry of tire particles originates in that industrial petrochemical recipe, what is left on the roadside or cast to the winds can be different. Some of the chemistry changes as tire particles age and are exposed to sunlight and other factors. The best-known - and most stark - of these transformation stories is that of the chemical 6PPD, which is in every tire sold, and which breaks down into 6PPD-quinone when exposed to ground-level ozone.
6PPD-quinone is one of the most toxic substances known for aquatic species, and it’s present in freshwater and saltwater ecosystems - washed there from roads by rainfall - as well as in air, soil, and human urine. We don’t know much about the impacts, but we do know it’s particularly toxic to salmon, as a recent “Owl in America” daily environmental newsletter from Rebecca Wisent at
explains:For decades, researchers had observed that coho salmon often became disoriented and died when entering certain streams to spawn and suspected a chemical running off roadways was to blame. The mystery was solved in 2020 when a group in Washington state published a study revealing the culprit, 6PPD-quinone.
Just a few hours of exposure can be enough to kill the coho salmon. The good news is that both the EPA and the state of California are taking action. The EPA, responding to a petition from the Yurok, Port Gamble S’Klallam, and Puyallup tribes, is looking into requiring tire manufacturers to find an alternative to 6PPD. California, Rebecca writes, “moved quickly to require tire manufacturers to disclose their use of 6PPD and research safer alternatives.” Washington and Oregon may follow suit. With EPA action under the next Trump administration in question, regulatory leverage from CA and other states may be our best bet to change at least this aspect of the tire industry.
“Solutions”: The complications of the Anthropocene mean that solutions to problems are often “solutions” that require further solutions, as suggested by the picture above. Likewise, the brave new world of EVs that’s coming complicates the already-difficult tire problem. For one thing, EV tires can wear faster because electric cars are able to accelerate and brake faster.
The main problem, though, is that EVs are up to 30% heavier than similar fossil-fueled cars, which can mean up to 30% faster tire wear and thus 30% more tire production. And that’s on top of a) the longstanding trend of SUV/truck car bloat/autobesity and b) the increasing demand - about 3% a year - for cars in the developing world. The good news, such as it is, is that innovation may eventually make EV batteries lighter, and that the industry is finally seeing some pushback to their oversized, pedestrian-killing cars and trucks.
The small amount of tire “recycling” that’s happening is rife with problems too. Nearly all of it is downcycling, turning tires into products of lesser value with their own environmental impacts. This includes pyrolysis, tire-derived fuel, and chopping up the toxic material for use in roads, playgrounds, sports fields, and other products. What could go wrong with using minced tires to line the places our children play? Well, the release of PAHs, pthalates, and heavy metals, for one thing, which is why the EU is looking to ban their use in sports fields.
Solutions: Actual solutions to the litany of problems throughout the life cycle of our tires are thin on the ground or difficult to enact, but here are a few to consider.
Better regulations will be fundamental, whether to improve the sourcing of natural rubber, to control the toxicity of tire recipes, or to radically increase the reuse and recycling of tire material. Societies, through their governments, need to regulate tires exactly as they now regulate tailpipe emissions. We need to set standards for how quickly tires wear out and what chemicals are used in their manufacture. A Guardian article notes that that UK research project on the environmental impact of tires found some low-hanging regulatory fruit:
The wear rate of different tyre brands varied substantially and the toxic chemical content varied even more, he said, showing low-cost changes were feasible to cut their environmental impact.
“You could do a lot by eliminating the most toxic tyres,” he said. “It’s not about stopping people driving, or having to invent completely different new tyres. If you could eliminate the worst half, and maybe bring them in line with the best in class, you can make a massive difference. But at the moment, there’s no regulatory tool, there’s no surveillance.”
If I was asked to create a slogan for this effort, it would be this: Tires are worse than tailpipes.
As for the certification of non-deforestation rubber, the Yale e360 article on rubber plantations notes that there has been plenty of talk in that direction, esp. in the EU, but very little progress. Rubber is a major cash crop for Southeast Asian nations, and there’s not much motivating the handful of powerful tire manufacturers either. Also, a certification process would be difficult to manage because so much rubber is grown by small growers who pass their product up through a maze of middlemen.
A better idea might be insisting that rubber trees be incorporated into large-scale agroforestry - growing a host of crops alongside the rubber trees and boosting biodiversity - rather than grown in monocultural plantations.
Tires are technological marvels as well as ecological nightmares, and so technological innovation will have to be part of the set of solutions. Some of it is straightforward: build lighter/smaller cars and trucks, and innovate better, lighter batteries. It will be more challenging, however, to design tires that are more durable, less toxic, quieter, and more recyclable and reusable.
Culturally, of course, replacing a significant percentage of cars and trucks with public transit, bicycles, e-bikes, and walkable neighborhoods would make a big difference. And for those of us in rural areas relying on cars, we would do well to drive less often and less aggressively. We all need to treat our tires as the poorly regulated, polluting, toxic beasts that they are.
That said, I’ll close by confessing that I’ve been shopping for winter tires for the Prius. More choosing between bad choices… But we have little choice, other than to risk the occasionally icy roads with all-season radials or choose to not go to work on snowy days.
We are, after all, just two of 8.2 billion people trying to navigate the world as it is.
Thanks for sticking with me.
In other Anthropocene news:
First, something cheerful from the BBC: A 74-year-old Laysan albatross that U.S. Fish & Wildlife named Wisdom has laid another egg in her nest at Midway Atoll. Wisdom is the oldest known wild bird, by far, and has raised at least 30 chicks.
And something beautiful and vital from
at : This week, Bryan writes elegantly about ferns, plant intelligence, and grace in the lead-up to the winter solstice.Some good news from Quitting Carbon, in the form of more (unnecessary) evidence that air-source heat pumps for the home are very capable of keeping you warm in very cold weather. I think the fact that heat pumps heat 60% of the homes in Norway should be evidence enough, but still it’s good to read that the U.S. Dept. of Energy conducted a two-year testing protocol for several heat pump manufacturers and found that certain models worked well down to 5F/-15C or lower (some down to -15F/-26C).
Something necessary from the Club of Rome, in the form of an open letter calling for serious reform of the U.N.’s climate conferences. Sent to all nations participating in the COPs, and signed by a multitude of the world’s top climate officials and environmental NGOs, etc., the letter makes clear that while the COPs have allowed for significant progress, the meetings as designed simply are not up to the task:
[the] current structure simply cannot deliver the change at exponential speed and scale, which is essential to ensure a safe climate landing for humanity. This is what compels our call for a fundamental overhaul of the COP. We need a shift from negotiation to implementation, enabling the COP to deliver on agreed commitments and ensure the urgent energy transition and phase-out of fossil energy.
From the Guardian, a fascinating long-form story on the under-reported phenomenon of land abandonment and its consequences with tens of millions of acres/hectares allowed to go (and grow) unmanaged by humans. The story centers on Bulgaria, where villagers have flocked to cities. The surprising part of the story is one that reveals the ancient complexity of human-landscape relations. Biodiversity is often better-served neither by abandonment nor by intense Anthropocene behavior but by small-scale traditional human activity. Put more simply, we’ve forgotten that we can be good for land and life:
“The essential role that people play in ecology is the critical thing, and it’s been ignored,” Ellis says. “The most biodiverse places left on Earth – this is almost universally true – have Indigenous people in them. Why? Well, they conserve a lot of that biodiversity and actually produce it. They maintain that heterogeneous landscape.”
There is no question that recent human activity – particularly the massive clearing of ecosystems and industrial consumption of fossil fuels – has been an ecological catastrophe. But for nature to be restored to a past version of itself, the question might be less one of human absence, than what form human presence can take.
Another long-read from the Guardian, this one digging into James Lovelock’s personal life to better understand how the Gaia hypothesis was developed. The idea, which revolutionized our understanding of Earth, was in large part developed by philosopher and systems analyst Dian Hitchcock, Lovelock’s colleague and secret lover.
From Vox, Changing with the Climate, a five-article series “exploring Indigenous solutions to extreme weather.” Each feature story centers an Indigenous community’s response to the world we’re making, highlighting how their deeper sense of relationship with the land provides ideas for the way ahead.
From
and his , a list of seventeen seminal papers on Earth’s water cycles, compiled for any of us motivated to understand the relationship between water and climate and then to act on that knowledge.From Inside Climate News, a good-news story of a microgrid powered by solar and tidal energy being developed in Eastport, Maine.
From The Conversation, an explanation of new research that confirms a slowing of the AMOC (Atlantic Meridional Overturning Current) is likely under the conditions of a warming Earth. For more information on this extraordinarily disruptive future, you can read my essay on it.
Excellent article, Jason! I knew only a fraction of the dangers you mentioned in tire manufacture, use, and disposal. The life cycles of our tires is very inimical to the environment it would appear. As always the problem is scale as you spotlight.. Cut one tree down, the world ecosystem doesn't notice. But cut 8 billion trees down and that same ecosystem is gravely wounded. There are simply too many of us. I don't think humans are very good at prioritizing avoiding the long term consequences of our technologies or scaling issues. Witness tires and plastics and fossil fuels.
We are stardust and rubber. Thanks, yet again, Jason, for bringing into focus the blurry truths we know and hold (sometimes repress) back there in our busy minds. It's essential and helpful to see the troubled world this way. (And thanks for the shout-out!)