Here's more information from the study:

https://www.ovoenergy.com/ovo-newsroom/press-releases/2019/n...

Here is an interesting bit:

‘64 million unnecessary emails sent every day is contributing 23,475 tonnes of carbon a year’ 64,317,204 unnecessary emails sent by Brits every day x1 email = 1g carbon = 0.000001 tonnes CO2e per email (Source: Mike Berners-Lee) 64,317,204 x 0.000001 = 64.317 tonnes CO2e per day 64.317 x 365 = 23,475.779 = 23,476 tonnes CO2e per year