[sophiabits]

There’s a French think tank called “The Shift Project” which actually produced a report estimating CO2 impact of data transfer a few years ago [1]!

The numbers are obviously very rough; there’s a LOT of factors to consider and which vary from one node to another. But the methodology is quite comprehensive, e.g. they factor in power consumption of the end user’s device while waiting for the data to transfer over the wire

Green software engineering is interesting to me because it seems like a good way to impact greenhouse gases _without_ requiring consumers to change anything about their lifestyle (which is the hard part of climate change…) There’s a cool presentation from Rasmus Lerdorf from around the time when PHP7 released where he estimated a 50% adoption rate of PHP7 would result in a saving of 3.5B kg CO2/year iirc, purely because of the compute efficiency gains from PHP6 -> PHP7.

I used their numbers to calculate that swapping our CI/CD clones at my day job over to shallow clones saved (maybe) 5.5 kg/week of CO2 emissions [2]. Not quite as impressive as the PHP7 figures, but I still think it’s kinda neat.

[1] https://theshiftproject.org/en/lean-ict-2/

[2] https://sophiabits.com/blog/the-cost-of-bandwidth

[okeuro49]

It was PHP 5.4 -> PHP 7.0. There was no 6.