Imagine the environmental impact of downloading all dependencies in a large project every CI run? and running it every commit of a pr? sometimes totalling in multi gigabyes. Crazy.

If your going to apply that logic, take a closer look at a lot of build chains out there.

This is whataboutism.

There is no way Apple's own development process was so wasteful as the waste they will bring to the millions of their own users.

If anything, the moment a company notices waste it goes towards reducing it.

Yes, that's bad too.

This is why we have local cache.

It’s actually basically nothing if you do the math… Let’s assume 50 million macs for a half hour at an average wattage of 20W TDP, wolfram alpha tells me worth that’s 360 metric tons of co2 , or about 24 USA citizens worth of co2 for a year. 24 <<< 300 million people in the USA, apple isn’t having much impact. I’d argue windows would be far worse anyway…

That's just one update.

Multiply that for every week throughout the lifetime of a mac and the benefits of delta updates are clear.

Building a 13" MBP produces ~200kg of CO2[1]. Taking GP's 50 million figure we get 10 billion tons of CO2. Very generously assume each one gets 1000 updates, you end up with 360,000 tons of CO2 total for all of these updates, or about 0.0036% of the cost of building them in the first place.

There are actual benefits to delta updates but the environmental impact isn't one of them.

[1] https://www.apple.com/environment/pdf/products/notebooks/13-...

Do Macs see a multi-gigabyte update each week? I haven’t noticed that. What do I overlook?

MacOS isn’t updated every week, or even every month.

The environmental impact of this decision is nothing compared to this one: https://news.ycombinator.com/item?id=26296339

(and the linked one is trivial to fix!)