What do you get for the Eco-Nut who has everything except a way to measure their neurotic guilt? How about “Industrial Designer” Nick Hunter’s idea for a wrist-worn device which gives you a monthly carbon allowance and monitors how you use them…

Introducing the Wearable Carbon Credit Meter.

[T]he carbon meter would fit on your hand and glows a particular color – green, yellow, orange or red – depending on how well you’re using your public transportation allowance. Are you saving more carbon by hopping onto a train for a short ride, or would the hybrid bus have actually had the smaller footprint? The meter would let you know.

Not only does the meter help you track your eco-sins, it could help Big Brother track them too. ZanuLabour would soil their lederhosen if they could get us all wearing these:

All the information about how many passengers are taking advantage of the various kinds of transportation would be uploaded to a government database where the data could be analysed and the transportation system greened up ever more.

This technology would also assist our rulers in keeping tabs on what everyone is up to, because all information would be beamed via WiFi to a Government database.
The wrist device changes colour depending on how you are getting along. If it goes red then, rather like in Logan’s Run, you will be executed by the State for the greater good. Except in this case it will be from above by huge death lasers which are currently being deployed in low Earth orbit. Or not.

This doesn’t exist YET but it’s only a matter of time.