To engage people, BEC uses Themes that provide a framework for discussion and action.
These are all the areas in which people take direct action to support sustainability. There are areas of indirect action as well, such as Education and Science. They are not direction actions, and therefore are not Themes, but can make projects better.
One benefit of Themes is that, by covering all actions, they cover all areas of interests. So, they help to engage everyone. They also connect people who have the same interests, such as in discussions on Waste, or Health. As well, the Themes make sustainability understandable to the average person. Once they understand all the Themes, they have a good working knowledge of sustainability.
Themes can be subdivided into sub-Themes. For example, Natural Capital can include water, wood, and other resources that meet human needs. We should note also that a project can include more than one Theme, such as with a Waste to Energy project.