Astronomers for Planet Earth is an international group of astronomers that are concerned about climate change. They work to document and improve the carbon footprint of astronomy, and to use our position as astronomers to promote awareness of climate change and the need to address it.
Rio Grande Waves is a group based in Las Cruces that is concerned with water issues, in particular, in the lower Rio Grande.
I have volunteered with New Mexico Wild, a group that works to preserve wilderness and public lands, doing both projects and as part of their Wilderness Defender program.
I have done volunteer trail work in the White Mountains Wilderness in New Mexico as part of the Smoky Bear Trail Crew.