https://www.coindesk.com/microscope-real-costs-dollar/
Looks like data was taken from places like: https://www.ecb.europa.eu/stats/policy_and_exchange_rates/ba...
and rest of the numbers were taking into account of how much each note costs to make.
"The Euro publishes sustainability statistics on their currency, and according to latest estimates, 3 billion banknotes printed in 2003 had an equivalent energy impact of 460,000 60W bulbs switched on for a year, which equates to 240 million kWh, or 0.87 million GJ. With circulation now at 15.8 billion notes, this would scale up to 4.6 million GJ (European Central Bank, 2007). To get to a global figure, for the purposes of this report, I will be multiplying this figure by a factor of four (i.e. a proportional share of global M0/M1 money supply). Therefore, we reach a figure of 18.4 million GJ, which would correspond to almost 3.07 million tonnes of CO2 equivalent."
This is just making a bank note, nothing about cost to distribute (guarding money, banking system, credit system).