Sorry if this does not quite fit into this sub, though I believe it fits in a way.
So I did a short calculation. I live in Germany. Lets say about 20% of jobs could feasibly be permanent WFH over here. Obv. not everything is possible as there is a large chunk of industrial and similar jobs that require you to be on location.
Now lets say those people average out to 15 kilometers of daily commute. The statistics I found say the average is 17 kilometers but they do not include people who don't leave their locality. Though you can assume that most jobs that could be WFH are simultaniously the jobs that require you to go to some far-off office building.
If we have 20% of the working population adapt to WFH that will come down to about 10 million people.
The average fuel usage is about 7 liters per 100km, people usually have about 6 weeks of vacation time and the weekends off. Adding to it the occasional week of sickness and holidays we can probably get it to 8 weeks not working in a year. So they go to work about 44 weeks per year.
Having everything set up we can now calculate the fuel savings if these 10 million people don't need to go to work. 15x2x44x5x7/100 = 462 liters per person or 4.62 billion liters.
To put it into perspective That is about 1848 Olympic Swimming Pools filled with gasoline saved every year. Or a bit more than 9 entire loads of a TI-Class Supertanker saved. Alternatively said about 12 Million Tons of CO2 every year.
Not to mention using at home solar panels would actually become useful as people would be able to use up their own production during the day.
The stupidity of desperately wanting workers to return back to the office is completely degenerate and not only because it is an asshole move but also because it quite literally destroys the environment.