Well written essay. Let me answer one point. Rocks are a sink for CO2 in the sense that carbonate rocks hold a lot of the CO2 generated in the past. I don't believe they are "eating up" the stuff going into the atmosphere now. Some atmospheric CO2 does go into the ocean, but this lowers the pH of the water (Dissolved carbon dioxide is called carbonic acid.) It's a weak acid but still acid.

I admire your efforts to reduce your "carbon footprint." Keep up the good work.