Bookmarked:
branch.climateaction.tech 
As an assumed 3.8% of global greenhouse emissions stem from “the digital world” (hard to define that more precisely, I assume), Laurent Devernay's primer on how to make web design more sustainable is probably not the cure, but an important step in the right direction.
Saving a bit of energy here and there, by smarter choices and what the author calls “functional sobriety”, may not seem like a much. Yet, we have to remember the scale of these things. Shaving a few kilobytes or a few requests off a web page is a minute saving for the single user, but can accumulate to enormous amounts when visited millions of times.
Nothing new, but I’m also glad that privacy-invasive tracking gets called out specifically: those are massive amounts of computing power, used to turn web users into subjects of corporate surveillance. If you want to start somewhere, start by getting rid of all the tracking on your site – future generations on this planet will thank you just as much as your company’s legal department.