What's the carbon footprint of a 4K Netflix binge? © Dan Bright

What’s the carbon footprint of a 4K Netflix binge?

Digging into the carbon impact of digital streaming.

We’re streaming more and more of the content that we watch – an Ofcom survey found that video-streaming services and other non-broadcast content were up 70 per cent more in 2020 compared to 2019. But what impact does this activity have on the environment? There’s no single answer to this question, but we can make a few assumptions and scribble on the back of an envelope to figure something out. (There has been some controversy about these kinds of numbers – here we’ll use the detailed estimates made by carbonbrief.org.)

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First, what are we going to watch on our marathon binge? Let’s pick one of the highest rated shows of all time: Breaking Bad. That’s 3,678 minutes, or about two and a half days of solid viewing, assuming no adverts and assuming we watch every precious second.

Different countries have different energy sources, so if we binged from our holiday home in France, where about 90 per cent of electricity is generated by low-carbon sources, we’d have a smaller carbon footprint compared to the UK. This time, let’s watch from the UK.

If we watch on different devices, then we will affect our carbon footprint – a mobile device can use 100 times less energy compared to a TV. Nevertheless, Netflix estimates that 70 per cent of their content is viewed on a TV, so let’s use that – we want to get the full cinematic effect of Breaking Bad.

If we streamed our show via 4G or 5G then this would also affect our carbon footprint. So, let’s use good old broadband, which should be slightly more efficient. However, let’s say our TV is a nice big 50-inch 4K model which uses more power and we’ll be streaming a larger amount of data to get that beautiful high-resolution picture.

Estimates by Carbon Brief have shown that for 2019, the data centre that stores the data was likely to use about 0.0139kWh (that’s kilowatt hours), transmission of the data would be about 0.0188kWh, and our big 4K TV would use about 0.1200kWh, equating to a total of 0.1527kWh, or 71.49g of CO2 per hour.

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Though this may be less since large data centres often procure cleaner energy compared to average – another estimate by the Carbon Trust puts the figure closer to 55g CO2 per hour on average in Europe. But let’s stick with our numbers. Our full binge of Breaking Bad would come to 61.3 hours at 71.49g CO2 per hour, so a total of 4.382kg of CO2.

In comparison, a typical electric car in the UK emits about 100g CO2 per kilometre (battery uncertainty and different models give some differences here), so that means you could have driven about 44km (27 miles) for the same carbon emissions as watching the show.

It’s worth noting that all of these numbers are likely to change over time, and should become lower as our technologies improve. We’re also likely to become ever better at estimating our impact on the environment. In fact, computer scientists at the University of Bristol have created a tool called DIMPACT, which aims to estimate the carbon footprint of digital video, games and music streaming, as well as publishing, advertising services and business intelligence. Netflix, BT and Cambridge University Press have already signed up to use DIMPACT, with others likely to follow suit in the near future.

So maybe one day we will have a complete and accurate breakdown of the environmental impact of every activity that takes our fancy. But for now, based on the numbers we have today, it looks like watching a high school teacher put his chemistry knowledge to dubious use on TV for two and a half days straight, is way better for the planet than going for a quick drive.

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