I love this little video by Redress in Hong Kong on the lifecycle of a white cotton garment. It just covers the basics of what is required to produce a garment, but it starts a conversation that needs to happen.
Here's another video, this one is a little more indepth. Watch the carbon emission counter in the bottom right corner of the screen.
AP Bio Carbon foot print project. The life cycle of a t-shirt and the co2 emissions from production, to transportation, to purchase, to the appliances maintaining the t-shirt.