I went and did some mafs.

This thing says the world consumes 180k TWh of energy per year.

This study estimates (with a considerable uncertainty) that the Internet amounts to around 5% of the world's energy usage.

Apparently, 48% of consumer web traffic is ads.. That is dystopian in itself, that means around half the content floating around the internet is stuff the client does not request but is pushed to them.

That would put the ad industry at 4500 TWh per year. However, this is back of the envelope.

Going off of this, a high estimate for crypto mining is 230 TWh.

That means the ad industry costs us around 20 times the cost of crypto in terms of power. Feel free to check me because I don't know shit about most of these things.

That said, this does not account for the entire ad industry, just the cost of sending internet ads around the world. Ads are made, ads are displayed in various media other than websites, and most importantly, ads have the sole purpose of driving further consumption, which all contributes to the societal costs of the ad industry.