If I remember this study right, they found "up to" 54%, under ideal, uncommon conditions.

The authors mentioned in the same study home office can cause even higher emissions than working in the office.

If true, this is just another sloppy meme journalism like the infamous "71% of all emissions caused by 100 companies", where they linked but misquoted the study in a similar way.

Yes, same study. I first saw it here: https://www.scientificamerican.com/article/working-remotely-can-more-than-halve-an-office-employees-carbon-footprint/

Study here: https://www.pnas.org/doi/full/10.1073/pnas.2304099120

All quotes from the study:

We find that, in the United States, switching from working onsite to working from home can reduce up to 58% of work’s carbon footprint, and the impacts of IT usage are negligible, while office energy use and noncommute travel impacts are important. Our study also suggests that achieving the environmental benefits of remote work requires proper setup of people’s lifestyle, including their vehicle choice, travel behavior, and the configuration of home and work environment.

Roughly speaking, if you live greener at home than your office is, home office can cause less emissions. If your office is greener than you are, working in office can cause less emissions.

So if you use more energy at home (e.g. by running A/C just for you), it would have been better for the environment if you went to the office.

Also the study says "up to 58%". How the heck does The Guardian manage to quote that as straight "54%"?? Was that the same journalist who butchered "71% by 100"? These numbers were wrong and out of context as well.