I freely admit, the following may be labeled 'geeky'.
I have a Bike statistics Googledoc (feel free to have a look) I've been maintaining since I started my biking back up. I very diligently clock my numbers in. It occurred to me to start embellishing it with a few extras. First I added in for this year, the days when I have to take public transport for whatever reason. Unfortunately that did prove that February is a really horrible month for cycling Not so good on the pocket, mind you. That gives me a calculation of total transport cost on a per journey basis versus the previous purely bike driven one (both are represented in the summary).
After that I added calculation that will show you the % of the Earth's circumference that I've cycled around. Okayyy not exactly the most life-useful stat, but quite sweet.
Now I've added a reference sheet for calculations and used fairly standard per kilometer figures for carbon production of tube, car, train and bus journeys to calculate a per day figure (I used Google maps to get the distances for the bus route, and the tube route), used a generalised figure of 221 for working days per year and found that a complete public transport working year from my house to Paddington would generate 509kg of CO2. that's a great figure as a reference - having so far generated 79kg (christ! 79! Myself, personally! That's dreadful) but very usefully as well, given that the figures don't change ie: they're not a cost in fiscal terms that changes, unlike public transport costs, I can easily apply them to previous years and give myself targets to beat.
Of course, what I really need is the carbon cost printed on any bike gear I buy, because with the best will in the world, the common preconception that biking is a zero carbon option obviously does not taking wear and tear in to account. Or indeed the cost of the bike in the first place. For standard inner tubes etc the carbon cost should be counted in total for one year, but for larger bike parts (wheels, or indeed, Kevlar tires) the carbon usage should be amortised over the expected lifetime of the part.
I'm really, really interested in the long term, almost 'bank account' nature of these kind of calculations. Particularly for the purchase of objects. Everything we do generates global warming emissions but particularly everything we purchase. If we buy seeds that grow, can we offset that carbon given that the seeds absorb carbon from the air in order to become plants? Heh. Yes, but then we eat them, and they generate methane, which is a teensy bit worse. Anyway. What I would *like* to see is this kind of carbon calc'ing becoming way more normalised. Even to the point of rationing. those who use less can sell it off - I've been through this before, but anyway, the point is that second hand goods can be treated as having a zero carbon effect. Although it's all rather bad for our capitalist economies, the focus on "Re-use" to use the old Bob The Builder-esque word ("Reduce, Reuse, Recycle!") to save people money or more to the point, to *make* them money is fab.
Of course, there's the slightly odd question which is: if you save up your carbon allowance and sell it off, what the hell do you do with the money, since you've used up all your carbon allowance. You can't actually buy much! Ah. Well. That obviously needs more thought. Presumably with the added low-carbon variable, the market would be flooded with low to zero carbon products (or you can just buy whatever it is you needed second hand?).
To be truthful, I doubt personal carbon management will happen until it's too late, and then its introduction will be a clonking, lumbering disaster because it'll have been done in a hurry. It would be way too controversial for any politician of any persuasion to attempt to drive through yet. So it's all a bit of idealistic desire. Or - geeky self generated charts, in any case :)
24 degrees tomorrow. In April.