One sustainable thing that I've been doing for years now is making my own brown sugar. It's so simple to do and saves the extra packaging that comes with buying those little cardboard boxes that contain brown sugar encased in plastic. Sugar can be purchased in the grocery store in large paper bags - that are a renewable resource and can be recycled - or, better yet, purchased from bulk bins at health food stores. The only other ingredient is molasses. Unfortunately, the molasses I have came in a plastic bottle; next time I purchase some, I will be looking for a glass bottle. However, since a little goes a long way, it's going to be some time before I need to buy more.
1 cup sugar
2 tablespoons molasses
Thoroughly mix molasses into sugar. Store in an airtight container.
The amount of molasses can be adjusted to make the brown sugar lighter or darker, depending on your needs.