For the data centre and network alone, a standard site (3 pages per visit) emits 1 to 2 tonnes of CO2e a year. In a full LCA that includes user devices, the figure is 2 to 5 tonnes. For context, that is the order of magnitude of one person's return flight from Paris to New York. It is significant for reporting, but rarely the first item to tackle in a company Bilan Carbone®.
Read the source article: Website carbon footprint: how to calculate and reduce it