Every day, people watch more than a billion hours of video on YouTube. According to a new study by researchers at the University of Bristol, all those hours add up to a large carbon footprint over the course of a year. They calculated that in 2016, people watching videos on YouTube resulted in approximately 11.13 million tons of carbon dioxide equivalent, a standard unit of measure that indicates carbon footprint. That’s similar to the amount of greenhouse gases emitted by a city the size of Frankfurt or Glasgow, Scotland, over a year.
We don’t usually think about the environmental impact of our internet use, but the researchers point out that today’s websites are designed in a way that’s inherently wasteful, using more electricity than is necessary to maintain the same user experience. That’s certainly the case with YouTube, and there are a few easy ways that YouTube could update its interface to make its entire service greener.
One common practice for users is to play a YouTube video just to access its audio. In their paper, which was presented at the annual ACM Computer-Human Interaction conference this week, the researchers show that YouTube’s carbon footprint could be meaningfully reduced if the company were to design a feature that would stop playing videos if they’re running in a browser tab that a user isn’t actively watching. If 25% of music videos are played in the background of a user’s browser, then YouTube could save 323,000 tons of carbon dioxide equivalent. This conservative estimate saves about 3% of the total annual greenhouse gas emissions associated with watching videos, and is about the same as the carbon footprint of 50,000 cars over the course of a year.
YouTube isn’t the only internet platform that has wasteful design that could be avoided. According to Chris Preist, a professor of sustainability and computer systems at the University of Bristol and one of the paper’s co-authors, other examples of digital waste include downloading documents to the same device multiple times, storing almost identical photos in the cloud, and video autoplay.
“The environmental impact of each of these for one individual will be small–so it isn’t something worth feeling eco-guilt about–but when totaled over global services, they could have a noticeable impact,” Preist tells Fast Company via email. “So spotting them, and designing to avoid them where possible, is worth doing.”