Do they count the forced upgrades of all clients ...
They will be way no matter how they try to look.... I wouldn't be surprised that Microsoft alone accounts for 10% of all "anthropogenic" carbon on the planet by them self. Think how many customers have been told over the last 30 years "that feature is supported in the next version" line from some sales rep.
Think about it, how often does a Microsoft software "Upgrade" not include new hardware in the mix.... how about the whole carbon footprint calculated from the dredging of the open air mines to a finished product also including shipping of these materials at every stage of refinement and manufacturing....
They some big claims and I 100% guarantee that they will be order of magnitude off from what ever they claim. Another lie by one of the biggest liars of all time.