Industrial designer Nitipak Samsen is concerned that "Global warming has been driven by capitalism, now we are trying to solve global warming through capitalism." He has developed a sort of mini-carbon offsetting device he calls a A.T.R.E.E.M. ((Automated Tree-Rental for Emission Encaging Machine), which measures the growth of the tree and the rate of carbon dioxide absorption. You enter your activity (a flight, an electric bill), swipe your card and it measures the growth of the tree that would represent the carbon offset.
The designer also has a simpler version:
I designed a tree measuring tape for children. This tape translates how much CO2 absorbed in the tree into the amount of activities rather than grams of CO2, e.g. 1 hour on a flight or 2 days of breathing.
Carbon offsets don't have quite the cachet they used to a couple of years ago; one just never knew where the money was going or if it was really making a difference. The idea that you can measure it in tree growth has nice symbolism. Via PSFK