Local environmentalism is to personal spirituality as global environmentalism is to organized religion?

That's an interesting way to put it! I suppose you can describe them as such, because local change in many different places translates to change at a larger scale, like the global level. My take on this is that if we have small scale changes all over the world, they are more meaningful that very large scale changes that may not be very effective. For example, many climate scientists argue that climate change mitigation and adaptation strategies are more effective when they are applied in a tailor made way to the local context. These strategies include the local stakeholders like the residents, businesses, and other people with conflicting interests to come to a mutually beneficial solution.

This is probably not the case if the strategies are implemented at an international level, where it would be impossible to include all the stakeholders and come to environmentally and socially friendly decisions. However, organising at a larger level can also have its benefits, such as international mandates for all cities to have a climate action plan (which can be further developed and tailored by the city's administration).