[happybuy]

As per your link, many of those other categories listed such as Video and Social media also contain as much as, if not more, advertisement load than perhaps even pure 'web traffic'.

The article was using the % of advertising resources in web pages – which came to 24% – as a proxy for the overall advertising resources across all internet traffic (which is difficult to accurately ascertain).

So, yes, this is a rough approximation... and the actual % of advertising resources on all internet traffic may be more or less.

However it is stating all digital advertising may be the cause 2% of global carbon emissions, not just due to the advertising on web pages.

[samatman]

That's a bad way to estimate that, unless one's goal is to come up with an absurdly high number which doesn't pass the sniff test. In which case they succeeded. It doesn't.