This has nothing to do with how green WMF operations might be. It has to do with the greener choices /we/ as volunteers can make for /our/ conferences.
Since a fortnight ago you were haranguing* the WMF for using too much air travel and lacking "any actual measurable commitment to picking up a telephone, holding a video conference, or holding a VR conference session", it will be interesting to see what solutions you can come up with for this conference you're organising. Did you consider the options other than an in-person conference that you recommended the WMF adopt, out of interest?
* https://en.wikipedia.org/wiki/Wikipedia_talk:Wikipedia_Signpost/2019-09-30/N...