Assessing the Carbon Reduction Potential for Video Streaming from Short-Term Coding Changes

As the impacts of climate change become evident worldwide, organisations across all sector of the economy are actively aiming at reducing their carbon footprints. Video streaming has been in the spotlight since the beginning of the pandemic. Previous work has identified opportunities to reduce electricity consumption, yet methods to reliably estimate the carbon reduction potential from interventions on video streaming systems are currently lacking. In particular, not enough consideration is given to the consistent methodological approach to impact assessment required to adequately account for the complex interactions between changes to a service and operational and structural effects at internet-scale systems at varying time scales. In this text, we review the state of knowledge and propose a consistent short-term marginal approach for the assessment of the short-term decarbonisation potential of interventions. We illustrate this with a simplified example intervention and contrast it to previous methodologically inconsistent approaches, in which we evaluate the temporary reduction of the video spatial resolution of user-generated content video on demand from 1080p to 720p in a fixed ladder scenario over one month in the UK. We find that the carbon reductions mainly come from savings at user devices, but are overall negligible at 0.5 gCO2e per day per typical laptop-viewer.