Money dollars are a pretty good “stand-in” but in general it’s better to reuse and reduce than to recycle.

But if the cost of a new machine is the same as a year or two of the old operating the new is probably the way to go.

> Money dollars are a pretty good “stand-in”

They aren't; among other things, most environmental harm is externalized. When you buy things that produce climate change or microplastics, the cost of the impact is paid by society generally.

I'm saying that I think "cost" in terms of money is not a good proxy for environmental impact.

> The cost of creating new computers has got to be pretty high to the environment

But aren't those made regardless if the people with old computers upgrade to them or not? I guess over time, they'll make less if people buy less, but the ones we'd purchase today has already been made, and might as well replace less energy efficient devices than just being added to the global count.

I think you answered your own question here.

We need an index of lifecycle costs for products and services, broken down by phase (material production, manufacturing, logistics, operations, disposal, etc.). It's especially needed because those costs are often externalized for buyers (i.e., they aren't built into the price - you don't pay the true cost of gas, for example; many costs are externalized to everyone else). How else can consumers, manufacturers, policymakers, etc. make anything like an informed decision?

I'm surprised someone like the Sierra Club, Consumer Reports, a scientific group, a government group, etc. doesn't undertake it. Yes, it's a bunch of work, there would be uncertainty, but it's essential and better than nothing.

There are such things for food:

* Klimato: https://klimato.com/

* The Big Climate Database: http://thebigclimatedatabase.com/

This is why people keep bringing up a carbon tax. It does a lot of the work to internalize all those externalities so individuals or groups don't have to try and figure all this stuff out.

Yes, unfortunately even the best intentioned individuals have very limited ability to make meaningful carbon-minimizing decisions. Carbon tax is such a sensible solution!