I spent a few years working for a small environmental advocacy group in small-town USA. One thing you could do is branch out your skills and learn GIS, then offer that to small groups who are doing environmental advocacy.
These groups are crazy desperate for more people who know how to use GIS software, because there are needs for good mapping in almost every single aspect of the work they do. The issue is that anyone who is good enough at GIS to be useful can get a job elsewhere making 2-3x more money. Maybe they don't get to go help release a rehabbed sea turtle back into the ocean during their lunch break at that other job, but cash is king I guess. At my org we had an ex-high school history teacher working part time learning to use ArcGIS from youtube so we could present results of a bicycle infrastructure plan to local city councilpeople. For another project we paid a shit ton of money (like, more money than was responsible to spend for an org. of our size) for an architectural firm to basically come in with their intern who knows GIS and create maps with overlays of how much money the city would save with new stormwater infrastructure in key places.
Do you know where those org put their job offers or accept remote worker? I found that most org with gis needs or consultancy gis companies tends to be super small in size and scale making it hard for an outsider to be considered as a potential applicant. I am on the other side of the coin, 3y working with GIS and remote sensing in agriculture, environment and public health. I am having a hard time finding a job to stay in the field (because searching in another country with a different language).
Based on my experience, full-time positions just specializing in GIS are probably extremely rare for this type of organization - hence the desperate need for someone who is good at it. Nobody in those places has time to learn/maintain skills in something like that.
A small-to-medium sized nonprofit does not have the time/money resources to hire very many specialists at all - everyone is wearing multiple hats and learning to do things on the fly that they have never done before. As an example, in my role within the span of 2-3 weeks I went from graphic design invitations/menu for $250-a-plate dinner party, to literally running food and filling drinks at that same party while also taking pictures for social media and washing silverware for the chef, to patching together a transition to a new donation payment platform, then the next week I was designing a social media marketing campaign. It's a constant "all-hands-on-deck" at all times, and nobody has time to specialize in anything.
In the case of GIS needs, an organization like this might rely on an "advocate" (whose main job is to lobby elected officials) to do some of this work because they did one project with it in one class of their Public Administration grad program. In my experience, even our semi-retired secretary who did mostly bookkeeping was "punching above her weight" in job responsibilities.
That's why I suggested it as mostly a volunteer-type gig if one is truly passionate about using tech skills to help the environmental movement. If you want to work for one of those places you need to be more of a generalist, and accept that your passion of GIS might involve doing what should be a full-time job in 25% of your time at work.
These groups are crazy desperate for more people who know how to use GIS software, because there are needs for good mapping in almost every single aspect of the work they do. The issue is that anyone who is good enough at GIS to be useful can get a job elsewhere making 2-3x more money. Maybe they don't get to go help release a rehabbed sea turtle back into the ocean during their lunch break at that other job, but cash is king I guess. At my org we had an ex-high school history teacher working part time learning to use ArcGIS from youtube so we could present results of a bicycle infrastructure plan to local city councilpeople. For another project we paid a shit ton of money (like, more money than was responsible to spend for an org. of our size) for an architectural firm to basically come in with their intern who knows GIS and create maps with overlays of how much money the city would save with new stormwater infrastructure in key places.