ONCE, we had to wait to watch television programmes when they were broadcast. Now, video on demand is taking over. Globally, more than 600 million people subscribe to streaming services like Netflix, and so many services exist that it is hard to keep track. This month alone has seen the launch of Apple TV+ and Disney+.
This is great if you are excited about Jennifer Aniston’s return to the small screen, or the prospect of a Star Wars TV show, but it isn’t so great when it comes to climate change. According to one estimate, online videos generate 300 million tonnes of carbon dioxide a year, or nearly 1 per cent of global emissions, and this is forecast to soar.
“1%
Estimated share of global CO2 emissions due to online video”
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This puts streaming in the same league as flying, which produces around 2.5 per cent of global emissions. Can it be true? And if it is, can’t streaming be made green by using renewable energy?
With broadcast TV, each transmitter uses lots of power to deliver TV signals directly to a huge number of people. But downloading or streaming video requires more equipment and energy because it is one to one, not one to many.
When you hit play on the next episode of your latest binge-watch, the request goes out to a vast data centre full of computers, which sends the video file in return. The video typically goes to a Wi-Fi router in your home that may send the signal to yet another box before it reaches the TV. Or, if you are watching on a phone, the video may be sent over the cellular network.
Totting up the resulting greenhouse gas emissions from all this is far from simple, but there have been a few attempts to do it. One, by Chris Preist and Daniel Schien at the University of Bristol, UK, looked at YouTube.
Earlier this year, they reported that the total emissions from people watching YouTube globally in 2016 was the equivalent of 10 million tonnes of CO2 – the same as from a small country such as Luxembourg. Mobile data accounts for the biggest chunk of that because sending data to phones takes more energy than sending it down a cable (see Graph). YouTube is a special case, though, as people are more likely to watch it on the go, says Preist.
The astounding figure of 1 per cent of all global emissions being due to online video comes from a French environment think tank called The Shift Project. It says that digital technologies produce 4 per cent of greenhouse gas emissions, with end devices being the single biggest source and data centres a close second.
Growing emissions
The Shift Project says the streaming of movies and TV shows by companies such as Netflix accounts for 34 per cent of the emissions due to video alone. This is followed by pornography at 27 per cent, with other streaming such as YouTube and videos on social media making up the rest.
There are uncertainties, but Preist thinks the overall emissions figure is in the right ballpark. However, this doesn’t necessarily mean that video streaming has led to a big rise in emissions.
Watching a movie on Netflix is better than driving to a shop to hire or buy a DVD. In fact, a 2014 study estimated that in the US.
But streaming video is worse than broadcast TV, because it happens in addition to broadcast and the energy used to transmit video increases with the number of viewers. Everyone expects video streaming and thus the associated emissions to rise fast. “Globally, loads more of us are doing it,” says Preist.
The growth of high-speed 5G networks will play a big part in this, by making it possible to download data faster. 5G uses less energy per byte than 4G, but energy usage will rise overall as people use more data.
So what can we do? Many streaming firms say they are using renewable energy. “We match 100 per cent of the power we use, and the power our partners use, through renewable energy and carbon offset projects,” says a Netflix spokesperson. “We prioritise use of renewable energy,” says an Apple spokesperson.
However, buying renewable energy from existing wind or solar farms does little to stop emissions rising. What matters is whether companies are creating additional renewable energy sources to cover the increased demand. This is something environmental organisation Greenpeace looks at in its Click Clean report evaluating the green credentials of tech firms. In the most , Netflix scored a D for not investing directly in new renewables, says the report’s lead author Gary Cook. “They have not really improved,” he says. “Buying renewable energy credits and carbon offsets does not really do much.”
A few firms, including Apple and Google, are building additional energy sources to compensate for their energy usage. YouTube was the only service in the video streaming category to get an A in the report, with Amazon Prime a distant second with a C. (Apple wasn’t rated in this category but got an A overall.) Yet such projects aren’t enough.
The planet will keep warming even if we use renewable power to stop emissions growing further. It will . That is hard to achieve if energy use is rising. Globally, renewables aren’t keeping up with energy demand.
“There is not enough of it at the moment,” says Sophia Flucker of Operational Intelligence, a UK company that helps data centres reduce energy use. We can’t keep adding more data centres and solar farms indefinitely, and building solar and wind farms still produces emissions, she says. Mining materials for data servers and disposing of old ones also creates environmental problems.
That means we need to limit demand. “There is no alternative to questioning our usage if we want to respect the commitments of the Paris Agreement,” says Maxime Efoui-Hess, author of The Shift Project video report.
The Shift Project is calling for what it calls “digital sobriety”. That means individuals and companies taking steps to limit energy use, such as turning off autoplay and watching at lower resolutions.
However, many people aren’t aware that streaming video is a climate issue and Preist thinks the onus should be on companies, not individuals. “Your digital carbon footprint is pretty small,” he says. “The overall footprint of digital is big globally because unlike aviation there are literally billions of us using it.”
People can do more to reduce emissions by changing how they travel, how they heat their homes and what they eat, says Preist. Using the internet less makes little difference in the short term because most equipment uses the same energy no matter how much data flows through it – the data centres are still running 24/7.
But reducing energy isn’t a priority for most companies, says Flucker – the focus of most data centres is on performance and reducing the risk of service failures. They are slow to make changes that reduce energy use even though it saves them money.
For instance, Preist’s YouTube study revealed that the company could cut up to 500,000 tonnes of CO2 emissions a year at a stroke. Many people stream YouTube videos just to listen to the music, so giving all users the option to stream audio only would save on all those wasted pixels. YouTube didn’t respond when asked if it plans to make changes.
For now, it seems the energy demand and greenhouse gas emissions from streaming videos are set to keep rising. Something to consider, as you click through to the next episode.
A new way to play
On 19 November, Google will launch its Stadia streaming service for video gaming over the internet. Instead of having to buy a computer or console to play high-end games, people will need only a Wi-Fi controller and a dongle for their TV. The games will run on servers in data centres.
Playing games typically requires more power than watching videos because of the graphical processing required. There are fears that streaming gaming in this way could lead to a jump in energy use and thus in carbon dioxide emissions.
“I don’t think we know yet,” says Chris Preist at the University of Bristol, UK. If people play over mobile networks – which will become possible with 5G – it will increase emissions, he says.
But it is more efficient to have few machines running constantly in data centres than lots of home consoles on standby and getting used occasionally. “If you buy less equipment, it might actually have a positive effect,” says Preist.
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