HD video streaming on a phone generates about eight times more in emissions than standard definition (SD), it says.
The report says digital technology’s estimated contribution to global emissions ranges from 1.4% to 5.9% of the global total.
Another simple way to save energy is for people streaming music to turn off any accompanying video if they’re just listening, not watching, the authors say.
They estimate such small moves could save up to 5% of the emissions from a streaming service – a reduction comparable to what’s achieved by running YouTube’s servers on renewable energy.
Another co-author of the report, Prof Corinne Le Querre from the University of East Anglia, told BBC News: “To be honest, digital tech is a small fraction of your emissions compared with, say flying even once a year – but every bit of CO2 saving is significant.