If I drive to work (which I don't about 95% of the time now), let's say I went about 20 miles round trip. My vehicle burns about 0.3kg CO2 per mile. That's about 6kg CO2. That bonfire cost an equivalent of over 12 trips back and forth, or 250 miles in my car- about two thirds of a tank of gasoline.
Most people see their actions as a set of balanced choices, whereby the fact that I commute to work rather than directly consume CO2 in my personal vehicle for 12 days "offsets" the choice to celebrate clearing a tree with a bonfire. That's OK, but the choice to commute is not carbon-free either. Between the bus and shuttle, what would be about 15-20 minutes of driving each way turns into a 50-90 minute commute on a shuttle and a bus or train. The bus costs $1.50 each way, the train $2.45. The shuttle is used either way. These options burn carbon too- but I have absolutely no way of computing exactly how much. I know the shuttle can't be good, since there's only about 10 people on the shuttle bus maximum when I commute, which is "early". Economically, it's probably cheaper to drive, especially if I use the train. But my concern lately is that commuting, for me, is emitting more carbon than the drive back and forth, and I wish I could actually compute the emission.
Another thing that's been bothering me lately is the tendency for (particularly rich environmentalists) to "buy" carbon credits. Not since the sale of indulgences has there been a more egregious method of expiating guilt, IMO. In principle, it's a good idea: it's like a voluntary tax on carbon emission. But waht's the point of rich coffers of environmental groups if they can't actually reduce carbon dioxide production? It seems like a modified Pascal's wager- the alternative, a dead planet, is too "horrible" to consider, so doing anything even though it might not actually be helping is better than nothing.