In fact, streaming your favourite one hour-long TV show is the environmental equivalent of popping four bags of popcorn in the microwave, or driving 250 metres in your petrol car, according to a recently published whitepaper from climate group Carbon Trust.
Last year, as the COVID-19 pandemic and the following lockdowns kept people around the world at home forcing them to turn to streaming services, Netflix has seen subscriber numbers surge to 16 million in the first three months of the year, giving the company its biggest growth spurt in history, almost doubling the new sign-ups it saw in the final months of 2019.
The pandemic also highlighted society’s reliance on ICT and particularly the internet infrastructure. Data traffic increased due to demands from home working, home education, and home entertainment. This increased awareness of the climate impact of ICT in general, including video streaming.
A whitepaper prepared by Carbon Trust – and backed by Netflix, which helped to fund the research – looked at the carbon footprint of watching one hour of video streaming from a life-cycle perspective just to find that the European average footprint is estimated to be approximately 55 gCO2e per hour.
For comparison, the emissions from microwaving a bag of popcorn for four minutes is about 16gCO2e, while driving 100 metres in an average petrol car emits around 22gCO2e, suggesting that at the individual level, the carbon footprint of streaming is very small compared to our other everyday activities. This is good news for streamers. Especially, that in the past years, there were numerous studies published on this topic with much higher carbon footprint estimates, going up as high as 3,200g CO2e per streamed hour.
So what is the explanation for the little consensus over the carbon footprint of streaming? For a start, Carbon Trust highlighted that the biggest variability relates to the country-specific electricity grid emission factor. For example, in Europe Germany’s grid emission factor is approximately 30 times that of Sweden, which translates directly to a 30 times difference in the overall carbon footprint.
The second most significant factor is the viewing device. It turns out the footprint of watching your favourite TV show on a 50-inch TV is roughly 4.5 times that of watching it on your laptop and roughly 90 times that of watching it on your smartphone.
Network energy intensity factors also vary by operator and by country, due to factors such as the age of network equipment, the topology of the network, population density, and even climatic factors such as ambient temperature and humidity.
The study underlined that forecasting the longer-term impacts of video streaming is more complicated, however large trends in the Information and Communication Technology sector (ICT) are driving down the carbon intensity of ICT services including video streaming.
Interestingly, the significant increase in data traffic during the global lockdowns did not have a similar impact in terms of energy use. Telecom network operators reported only marginal (less than 1 per cent) increases in energy consumption, despite increases in data traffic of up to 50 per cent.
The study highlighted that large data centre cloud providers are increasingly purchasing renewable electricity, many with 100 per cent renewable targets, with some already at 100 per cent. Similarly, several major telecoms network operators have 100 per cent renewable targets, and an increasing number are setting approved 1.5°C compatible science-based targets.
The end-user viewing devices are also becoming more energy-efficient due to a mix of technology advances, regulations and standards.
The whitepaper set out many opportunities for further research to improve and add to the evidence base. It should be regarded as a work-in-progress, however, it is clear that we have to keep an eye on the impact and context of video streaming, as in the future, the associated internet traffic could have impacts on the total energy demand of the internet.