Most GCSE Computer Science courses have a section on the ethical, legal, cultural and environmental impact of computers and their use. This page contains a list of examples that I share with my students for discussions of this topic, and which would be used when answering exam questions. The list is updated on a regular basis, and I don't bother with obvious issues, such as the use of paper.
NB. I haven't included obvious issues, such as the use of paper and electricity.