While most of the online traffic - 34 percent - is related to streaming videos, on Netflix, Amazon Prime, and Hulu, for example, the next biggest sector is online porn.
"Digital videos come in very large file sizes and (are) getting bigger with each new generation of higher definition video," said Gary Cook of Greenpeace, which monitors the IT sector's energy footprint.
"More data equals more energy needed to maintain a system that is ready to stream this video to your device at a moment's notice," Cook told AFP. Much of the energy needed for streaming services is consumed by the data centre, which delivers data to your computer or device, explained Cook. The centres contribute about 0.3 percent of all carbon emissions, according to an article by Nature.
"For energy consumption to stay flat for the next five to 10 years, significant improvement in IT equipment and data centre energy performance must be made or our appetite for computations must diminish," said Dale Sartor of the Center of Expertise for Data Centers, linked to the US Department of Energy.
Anders Andrae of Huawei Technologies told AFP he estimated they would consume as much as 4.1 percent of global electricity by 2030. Web-based video traffic is expected to increase four times from 2017 to 2022 and account for 80 percent of all internet traffic by 2022, according to the CISCO Network.
Netflix is continuing to expand globally - the company reported a 53-percent increase in international revenue for streaming subscriptions between 2017 and 2018. And Disney and Apple are launching their own streaming services this year.
Meanwhile, the equipment used to view videos is getting larger - the average screen size shot up from 22 inches (55 centimetres) in 1997 to an expected 50 inches by 2021, according to the Consumer Technology Association.