on the topic of personal CO2 footprint accounting, it is surprising how much of an impact one can do, similar to Oilerlord's situation. I use a rough percentage for a typical US American, our footprint is roughly 34% vehicles, 33% residence and 33% the remainder (air travel, food, work offices ....). Obviously the fraction is different for location as well as personal situation. I believe it's 40% for vehicle in California.
In theory, one can generate sufficient roof-top power to cover the first 2 categories: EVs, residence heatpump for heating & hot water, insulation etc... The remaining third can roughly be addressed with food choices, less consumption, recycling, turn office lights off etc.... The idea is not to reduce the footprint to zero, but to minimize it.
The low hanging fruit is obviously EV, then residential.