At a Glance

The carbon footprint of a smartphone depends, in part, on the amount of usage.The carbon emissions generated by smartphonescome primarily from the data centers serving them.By 2040, smartphones and their data centers will be the environment's most damaging information and communications technologies.

It's not a stretch to assume that smartphones can't be good for the environment, but a new study suggests that the carbon footprint of the device held by 2.5 billion people worldwide is much larger than people realize and growing at an alarming rate.

Researchers from Ontario's McMaster University analyzed the information and communication industry (ICT), which includes theproduction and use ofPCs, laptops, monitors, smartphonesand servers. They found that by 2040, information and communications technologies to the environment, according to a press release.

On their own, to the environment by 2020, according to the research publishedearlier this month in theJournal of Cleaner Production.

While smartphonesconsume little energy themselves to operate,85 percent of their carbon footprint comes from their production, including the high environmental and human price that comes frommining the precious metals needed to produce them.

In addition, their short lifespan drives the production of new models at "anextraordinary amount of waste," the authors note.

“Anyone can acquire a smartphone, and telecommunications companies make it easy for people to acquire a new one every two years," said Lotfi Belkhir, lead author of the study and associate professor at McMaster's W Booth School of Engineering Practice and Technology. "We found that by 2020 the energy consumption of a smartphone is going to be more than that of PCs and laptops.”

The usage and number of smartphones worldwide continues to grow. According to Statista, there are 2.53 billion users of smartphones worldwide today, which doesn't take into account all other mobile devices like cell phones and tablets. By 2020, .

To drive sales, many U.S. telecommunications companies are now offering plans like and , which allowusers to upgrade to a new phone every year instead of every two years.

Usage Drives Carbon Emissions

The carbon footprint of a smartphone depends primarily on usage, the researchers say. This is because the vast majority of carbon emissions generated by smartphonescome from the data centers behind them.

“For every text message, for every phone call, every video you upload or download, there’s a data center making this happen," said Belkhir. "Telecommunications networks and data centers consume a lot of energy to serve you and most data centers continue to be powered by electricity generated by fossil fuels. It’s the energy consumption we don’t see.”

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Mike Berners-Lee, a leading expert in carbon footprinting, found that in 2010 led to a carbon footprint of 100 pounds of CO2 each year. At one hour of usage per day, the amountjumped to nearly 2,800 pounds per year. Globally, Berners-Lee concluded that users emitted 125 million tons of CO2 each year.

That was in 2010when there were , according to theInternational Telecommunications Union. In 2017, that number hadgrown to 7.7 billion.

Thestudy notes thatthe information and communication industry now accounts for about 1.5 percent of the total global carbon footprint.

"If trends continue, ICT will account for as much as 14 percent of the total global footprint by 2040, or about half of the entire transportation sector worldwide,” Balkhir said.

In light of their findings, the authors say the industry must take immediate steps to mitigate the carbon footprint of smartphones. One recommendation is to adopt renewable energy as the primary source of energy at data centers instead of fossil fuels.

"The good news is Google and Facebook data centers are going to run on renewable energy. But there needs to be a policy in place so that all data centers follow suit. Also, it’s not sustainable to have a two-year subsidized plan for smartphones,” Belkhir said.