We put a lot of miles on our tires each year, and all those miles are bound to cause wear and tear. Without proper tire maintenance, you can run the risk of dangerous blowouts, but even with proper maintenance, tires have a shelf life and must be replaced at least every six years or when the tread gets at or below 2/32nds of an inch [16]. While having to buy new tires is a burden on our wallets, it’s also a burden on the environment.
Which got us thinking—how badly, exactly, do tires affect the environment when they are, well, retired? We’ve done some digging into tire waste and recycling, and the results are eye-opening, to say the least. Below, we’ll explore some shocking end-of-life tire (ELT) statistics.
Key Insights
- Globally, an estimated 4 billion waste tires are in landfills and stockpiles and half of those (about 2 billion) are in the U.S.
- 1 billion waste tires or End-of-life tires (ELTs) are disposed of each year globally [7]
- Tire waste makes up 2% of global solid waste.
- In the U.S., more than 280 million waste tires are generated each year or about one tire for every person in America.
- 16% or 45 million tires end up in landfill in America.
- 4 in 5, or 81%, of waste tires in the U.S. are recycled, with more than half being used as tire-derived fuel.
- Globally, 70% of the tires are recovered and 50% of tire waste is actually recycled.
- Europe leads the way in tire waste management with only 4% tires ending up in landfill vs 28% worldwide average.
- 3 billion tires were produced worldwide in 2019 alone [9]. More than 1.6 billion new tires are generated in the U.S. each year [6]
- 15 million commercial tires are retreaded each year in the U.S. and Canada [14]
- The U.S. tire recycling market is worth $1.4 billion; the global market size is $5.12 billion [11, 12]
- Tires can take up to 2,000 years to fully decompose [3]
- Car tires use about 7 gallons of oil to make; a truck tire uses about 22 gallons [4]
- 28% of the microplastics found in our oceans comes from tire wear and tear [5]
TIRE STATS
How many tires are generated annually?
More than 1.6 billion new tires are generated in the U.S. each year [6]. Globally, these numbers are typically double that, with about 3 billion tires produced in 2019 alone; while numbers have been lower in recent years due to the pandemic, they are expected to rise once again [9].
Average lifespan of a tire
So, just how long will all those tires last? It’s difficult to give an expected lifespan for tires as a whole, as all tires are different. It also depends on how well drivers keep up with tire maintenance. However, it’s generally accepted that the average tire should be replaced or, at the very least, inspected every 6 years [10]. After 10 years, tires should be replaced, regardless of tread levels [10].
The U.S. Tire Manufacturers Association (USTMA) notes that tire manufacturers provide warranties which can range from 30,000 miles to 80,000 miles; however, most new tires today should last about 60,000 miles, assuming they’re properly cared for [10].
How many tires are discarded every year in the US?
ELTs create a huge waste problem. Roughly 1 billion waste tires are generated each year globally [7]. In the U.S. alone, 280 million tires are discarded annually [3], while in Europe about 300 million tires
While these numbers are staggering, the good news is that these numbers have drastically decreased over the last three decades. In fact, between 1990 and 2017, the number of stockpiled tires decreased by roughly 94% [4]. This is largely due to the rise in the tire recycling industry.
TIRE RECYCLING
Tire recycling market
The tire recycling industry is a lucrative one, with a $1.4 billion market size [11]. Globally, the market size is at an estimated $5.12 billion, with projections to rise by $2.2 billion by 2031 [12].
How many tires are recycled?
Out of the 1 billion waste tires generated each year globally, only about 350 million—or 35%—are processed by the tire recycling industry each year [6, 7]. In the U.S., 225 million or 81% of waste tires are recycled while Europe has the highest tire recycling rate of 96%.
What happens to recycled tires?
Tires are made for safety and durability, which is what, in turn, makes recycling them such a difficult and expensive endeavor [1]. Sure, they can be retread and reused (more on that later), but not indefinitely, at which point they must be disposed of or recycled. Still, shredded or ground tires can be turned into rubber mulch or used in a number of different applications, from roadways to sports fields, building materials, and playgrounds.
In America,
- 43% of the waste tires are used as tire-derived fuel.
- 25% are used as ground rubber.
- 8% are used in civil engineering.
Other options for ELTs
Retreading is another option, which involves remanufacturing a tire to replace worn tread with new tread, therefore extending the tire’s life by up to 200% [14]. Retreads are used largely by the trucking industry, accounting for about 44% of all commercial tires on the road in both the U.S. and Canada [14]. In total, about 15 million commercial tires are retreaded each year in the U.S. and Canada, offering safe, reliable, lower-cost options which are comparable to new tires [14].
Below are some statistics which showcase the environmental impact of the retreading industry [14]:
- Retreading saves the U.S. and Canada 217.5 million gallons of oil which would otherwise be used making new tires
- It also keeps 1.4 billion pounds of waste out of U.S. and Canadian landfills
Energy recovery
Tire-derived fuels (TDF) refers to burning tires for energy [4]. TDF is another option for ELTs and is common practice in cement kilns, thermal power stations, paper mills, steel mills, and more [15]. By using ELTs as fuels, various plants can make use of tires’ high energy content that rivals alternative fuel options like coal [15]. Many tires are burned in special facilities which can cleanly do so for energy recovery [4]. However, tires that aren’t burned or recycled into things like running tracks end up in landfills.
LANDFILL
The problem with landfills
About 16% of tires end up in landfills in America, and the worldwide average is around 28% [4]. At 4%, Europe has the lowest percentage of waste tires going to landfill.
Currently, about 4 billion tires are taking up space in both landfills and stockpiles worldwide [7]. This is especially troubling considering 75% of the tire is void, creating an unnecessary waste of space in landfills [13].
Another issue is that these mountains of tires can catch fire, and, while rare, tire fires create serious air pollution and are incredibly difficult to stop [7].
How long does it take a tire to decompose?
What’s more, tires take an astounding amount of time to decompose. According to estimates from the South Carolina Department of Natural Resources, tires can take up to 2,000 years to fully decompose, on average [3]. Of course, it’s important to note that decomposition depends on a number of factors, including temperature and moisture levels as well as the positioning of the item, namely whether it is buried or exposed [3].
For comparison, here’s how long it takes several other common items to decompose [3]:
- Vegetables: 5 days to 1 month
- Paper towels: 2-4 weeks
- Cardboard: 2 months
- Banana peels: up to 6 months
- Cotton t-shirts: 6 months
- Rubber boot soles: 50-80 years
- Aluminum cans: 80-100 years
- Disposable diapers: 500 years
- Computer ink cartridges: up to 1,000 years
- Styrofoam: never
When we look at tires compared to these other items, it isn’t surprising they take so long to break down, considering their makeup.
Environmental impact
Tires are made up of roughly 19% natural rubber, 24% synthetic rubber (a plastic polymer), and the remaining material is comprised of metal and other compounds [4]. There is a significant amount of deforestation that comes with sourcing natural rubber, not to mention the fossil fuels required to produce synthetic rubber; car tires use about 7 gallons of oil to make, while a truck tire uses about 22 gallons [4].
What’s more, tires themselves contain oils and other pollutants as well as heavy metals including lead, which contaminate the environment as they decompose in landfills [3].
The issue of microplastics
But it isn’t just the end of a tire’s life which causes problems. Tires are a major contributor of microplastics while they’re on the road [4]. In fact, up to 28% of the microplastics found in our oceans comes from tire wear and tear [5]. As the rubber wears on the road, bits of tiny synthetic plastic are thrown onto the road, which is eventually washed off the road and into the water system [4].
FUTURE OUTLOOK
Tire recycling challenges
Thankfully, it’s not all doom and gloom. Tire mogul Charles Goodyear first developed tire curing (the process that gives a tire its shape, form, and tread pattern) back in 1850 [1]. This process combines sulfur with natural rubber, which causes a chemical reaction that turns the liquid mixture into rubber [1]. While great for creating tires built to last on the road, this process makes tires difficult to break down for recycling. However, a group of chemists at Ontario’s McMaster University recently discovered a way to break these tires down by breaking the chemical bond created during curing in order to more easily reprocess these tires and turn them into new products [1]. This process is likely to prove expensive at an industrial level; however, it is a step in the right direction [1].
Sustainable options
There’s also been a call for more sustainable tire production. In 2017, researchers associated with the University of Minnesota were able to produce isoprene, one of the key ingredients in synthetic rubber, out of corn, grass, and trees, rather than traditional fossil fuels [4]. Elsewhere, engineers at Michelin tire company announced their plan to make new tires from 80% renewable materials, including wood, straw, and even beets [2]. And Goodyear revealed a concept tire made not only from recycled rubber but containing moss in the middle, which would help to absorb carbon dioxide during each journey [4]. These may seem like wild concepts, but then again, there’s also been talk of insect burgers to offset the negative environmental impact of the meat industry, so there’s that.
Conclusion
While tires are a major detriment to the environment, the tire recycling industry is hard at work to breathe new life into old tires. With research into more sustainable production and advances in recycling technologies, we are likely to see progress as it pertains to ELTs. Hopefully, articles such as this one can help to spread awareness of the damage tires have on our environment, thereby leading to further research and development regarding sustainable tire solutions.
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- The Conversation
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