Just a random curiosity question here. How much do all the holiday lights and other such decorations affect the environment? Relative to the footprint of a house a set of outdoor lights is probably pretty minimal, but if you add up all the decorations of all the houses, what does it come up to?
I think you could do this basically by weight, coupled with embodied energy costs of the principle materials.
E.g. Christmas Lights. The bulk of the material of concern is the PVC insulation. My guess is that the environmental footprint of a string of outdoor lights is on par with a single section of PVC house siding.
Plastic ornaments: Plastic, but they will last for years. Considering that there is probably less plastic in a couple dozen ornaments than there is a plastic milk jug, I suspect that transport is the main environmental cost.
Glass ornaments: Glass has higher emboddied energy, but glass is endlessly recyclable.
Artificial trees: Higher initial cost in terms of oil, energy, but they are re-usable for a decade or two.
This is a "Re-arrange the deck chairs on the Titanic" question.