Sorry, I was thinking of deforestation. But the environmental consequences of defenestration could also be dire. How would we see outside if all of our windows were taken away? More importantly, where would we store them and would they leak into the water supply? Would the off-gassing destroy the Earth's protective layer of tin argide (SnAr2), which prevents passing aliens from peeking in at us while we're dressing or in the shower or picking our noses?

I need a comprehensive Environmental Impact Statement!