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Smartphones are the world's most popular consumer electronics device, with around 4.5 billion in use last year, according to Deloitte. Meanwhile, smartphone makers continue to churn out new versions of their products every year, and we keep buying more.
It's natural to wonder, then, what kind of environmental impact all these smartphones are having on the world. How much is the device in your pocket contributing to global emissions? What about the damage it may do to the environment before or after it's in your possession?
All these smartphones generate 146 million tons of CO2 or equivalent emissions (CO2e), Deloitte's Technology, Media, and Telecommunications division estimated in its comprehensive TMT Predictions 2022 report. Meanwhile, the internal components of smartphones can be made of toxic metals, making them difficult to safely dispose of.
But tracing the environmental footprint of a single smartphone is hard to determine. It's difficult to say just how "green" your smartphone is, given how many different elements are involved in its production.
Tracking emissions and other harms
One thing is clear, however: The production of a new smartphone has a far greater environmental impact than actually using one. So for consumers concerned about their own impact on the environment, the greenest move they can make is to hold off on buying a new device for as long as possible.
"There are lots of steps in the manufacturing process which are quite energy intensive," says Paul Lee, Deloitte's global head of research for tech, media and telecoms. "So by the time the phone arrives in a box, in the consumer's hands, the vast majority of the lifetime emissions of that device would have been emitted."
The bulk of 2022 smartphone emissions -- an estimated 83% -- came from the 1.4 billion devices produced just last year, Deloitte says. That includes emissions from manufacturing the phones, shipping them, and their first year of use.
A brand-new smartphone generates an average of 85 kilograms in emissions in its first year of use, with just 5% of its emissions coming from actual usage -- most of the emissions come from mining raw materials and the rest of the manufacturing process.
"What the consumer has in their hand is something quite sleek and shiny, but the step before that involves lots of extraction of raw materials," Lee says.
There are certain elements necessary for electronic devices that come from countries and regions currently in conflict, creating more challenges and risks associated with their extraction. This includes "essential components which aren't needed in any great quantity, but they're essential," Lee said. "So that's what creates the friction point."
Then, refining raw materials and assembling components take place in very controlled environments. For example, up to 30% of a semiconductor fabrication plant's operational costs come from the energy needed to maintain constant temperature and humidity. Semiconductor factories have to be very close to a major source of energy and are often near a major source of water to support the manufacturing process.
By this point, the building blocks of your smartphone have already traveled through many hands -- from those responsible for acquiring the raw materials, as well as the many vendors that make different smartphone components. For smartphone vendors -- not to mention the consumer -- it can be challenging to track the carbon emissions footprint and the greater environmental impact of each device up to this point.
"It's a huge challenge for smartphone brands -- actually understanding the emissions that go into creating that device," Ben Stanton, technology, media, and telecoms research manager at Deloitte, tells ZDNET. "They may not have perfect visibility all the way down the supply chain. So if they -- as a central player in the creation -- struggle, then for the consumer to really comprehend all of those things is very, very challenging."
How green is the greenest phone?
Among smartphone vendors, Apple claims to have one of the "greenest" devices. According to the Product Environmental Report for the iPhone 13 Pro, the device has a 69 kg carbon footprint throughout its entire life cycle, from production to recycling -- notably better than the 85 kg in emissions an average smartphone produces in just its first year of existence.
It's not surprising Apple can boast a relatively "green" phone, given the company's size and worth, which gives Apple more leverage over its suppliers. Still, the "greenest" aspect of an iPhone may simply be its available lifespan. The latest version of the iPhone's operating system, iOS 16, is compatible with models going back to the iPhone 8, which was released in late 2017. This means iPhone 8 users can continue to use their nearly six-year-old device, knowing Apple is protecting it with the latest security updates.
Samsung last year started offering up to five years of security updates to help protect select Galaxy devices. Other manufacturers only offer two years.
Considering that the typical lifespan of a smartphone falls between two and five years, Deloitte estimated that the average smartphone generates an average of just eight kilograms of emissions from actual usage during its working life.
"The actual usage of a phone is really, really trivial" in terms of emissions Lee notes.
How trade-ins help
When you're ready to get a new phone, the green option is to take advantage of one of the many trade-in deals that mobile carriers provide. Then, your old device can be resold, thereby lessening the demand for new devices.
"An iPhone 11 or an iPhone 12 may be an old device for you, but there are many markets where they want that device but can't afford to spend the $800, $900 or $1,000," Biju Nair, who leads the Connected Living business for Assurant, said to ZDNET.
Assurant is a risk management business. Among other things, its Connected Living segment runs device trade-in programs for mobile carriers. Carriers like AT&T and T-Mobile typically offer customers incentives to bring in their old devices, allowing people to trade them in for newer phones. Assurant provides software that gives carriers to value of a device coming in, and it helps the carrier verify that the device isn't stolen.
"Every device that is collected, or the vast majority of them, gets repurposed, in some way, shape or from," Nair said.
While the trade-in programs help make the smartphone market greener, they also are financially appealing to mobile carriers.
"As a consumer, when you get money in your pocket, you're inclined to spend more of that money in the store," Nair explained. "So you came in to buy an iPhone 14, and you might end up buying an iPhone 14 Pro, you might buy a set of AirPods."
Trade-in programs are driving the growth of the used smartphone market, research firm IDC reported. Worldwide shipments of used smartphones, including officially refurbished and used smartphones, came to around 282.6 million units in 2022, IDC said -- that's a double-digit increase over the 253.4 million units shipped in 2021. IDC forecasts that used smartphone shipments will reach 413.3 million units in 2026.
Nair called the trade-in programs a "win-win-win" for everyone involved -- customers get money for their old device, carriers get more sales, and consumers in other markets get access to devices they otherwise couldn't afford.
"And it's exceptional for the environment," he added, "Because these devices don't end up in landfill."
Where recycling fits in
When a device is truly at the end of its life, some components can be recycled. According to California's Department of Toxic Substances Control (DTSC), 80% of a cell phone can be reused. Precious metals contained within the circuit board such as gold, silver, and platinum are the most valuable commodities.
According to voluntary survey reporting data, 3.66 million cell phones were recycled in California in 2021, the DTSC told ZDNET. The department suggests that the state's strong recycling record received a boost from the California Cell Phone Recycling Act of 2004, which requires cell phone retailers to collect used phones for reuse, recycling, or proper disposal at no cost to the consumer. Since 2019, the estimated recycling rates of cell phones sold and recycled in California have risen from about 19% to 35%.
The technology enabling smartphone recycling continues to improve. In 2020, Apple debuted a new recycling robot called "Dave," which disassembles an iPhone's Taptic Engine to better recover key materials like rare earth magnets and tungsten. It also enables the recovery of steel, after the Apple robot named "Daisy" disassembles the iPhone's various components.
Deloitte's Lee is optimistic about the smartphone market becoming more sustainable, simply because greener business practices align with market economics. Top tier phones don't change much from one generation to the next, Lee noted -- giving consumers reason to hang onto their devices longer, or to consider used devices.
"The rate of change in the phone isn't going to be as big as it was over the last eight years," he said. "So that means that their longevity will become greater. It's not necessarily that consumers are choosing to lower emissions... They may just prefer to buy a five year-old prestige phone than a brand new budget phone."