I just had an epiphany last night, I gotta talk to elon musk. Pretty much deal with rising water levels on earth and colonizing the moon. Start by building living stations with indoor gardens under lights to keep the light schedule right. have the plants producing food and oxygen. While this is all happening be bringing tons of water to put into craters and reservoirs. use the water for the plants and drink, and perhaps over tens of thousands of years, the water in craters and extra gasses put out will create some sort of atmosphere around the moon.
This is just a stoned idea, and Im sure scientist have already thought of something similar. But it seems like a decent start, even if its just large domes to create the atmosphere in first. And Im not sure if the moon has enough gravity to keep the air there, or if solar winds would blow it away, but I think its completely doable/tryable. If you've seen Bio-dome you know what im talking about. lol