I would definitely call it a byproduct as per definition it is “an incidental or secondary product made in the manufacture or synthesis of something ”
The reason for those byproducts, in that matter would be us, as we have evolved to a species altering our surroundings and for example learned to produce electricity.
There ought to be silence 
byproducts or the reason?
I would definitely call it a byproduct as per definition it is “an incidental or secondary product made in the manufacture or synthesis of something ”
The reason for those byproducts, in that matter would be us, as we have evolved to a species altering our surroundings and for example learned to produce electricity.