April 7, 2008 - Contrary to popular myth a “carbon footprint” isn’t something left by a tyrannosaurus rex a few thousand years ago. Neither is it the black skid mark left by a Mustang going from o to 60 in under 6 seconds once the light turns green. Rather it is a measure of the amount of green house gases, measured in units of carbon, resulting from human activity.
For example, when you produce steel studs or plastic bags, a certain amount of energy is used in the manufacturing process. This energy tends to be produced by something that releases carbon into the air. Almost every time something is burned or heated carbon is a by product. Some things are carbon neutral. For example, when a tree grows it converts carbon into wood fiber. When it is burned it puts back into the air the carbon that was removed as it grew.
However it doesn’t stop there. A steel building because of steel’s thermal conductivity usually takes more energy to keep warm and cool through its life time than a wood building since wood tends to have higher insulation values. Thus a wood frame building should have a lower carbon footprint over its lifespan than a steel framed building. In other words all things being equal a wood building is the more environmental choice in terms of a carbon foot print, just as is the paper bag a better choice than a plastic one. Although in all fairness the optimal choice would be a reusable bag (which of course could also be made from wood fiber).It gets more interesting since younger trees remove (sequester) carbon at a faster rate than older trees so constantly cutting trees (lets call them carbon storage units) and planting young ones will reduce the forest’s carbon foot print (depending upon soil disruption during harvesting), especially if the trees are converted to uses that have long life spans like buildings and that use lower energy manufacturing processes. A water wheel powered sawmill employing workers living next to the mill who walk to work and have local farmers markets and shops within walking distance would have a very low carbon footprint. Of course this is the same description as a company town (oops!).
Now all of this so far is fairly easy to document by some straight forward science. That’s where the fun ends. The chart below shows my carbon footprint as calculated by one of a dozen online quickie carbon calculators. Primarily because of my foreign travel (that I do to promote carbon neutral development otherwise know as sustainable forest management) my carbon footprint is much larger than the average US citizen which is the largest in the world.
For an even scarier look at carbon credit based solutions check out the British column by George Monbiot at the link below:
http://www.monbiot.com/archives/2008/02/19/an-exchange-of-souls/#more-1103
