Sustainable consumption - what is it all about?

Sustainability is one of those terms like "globalisation" or "governance" that seem to suffer from their own popularity. As they are thrown in in all sorts of debates and discourses, it becomes difficult to register what exactly they mean. So, I am first of all hoping to leave this course being clear on what the concept of sustainability - and of sustainable consumption - actually entails. This is surely the first step to being able to analyse and evaluate policies that are designed to give citizens incentives to live and consume more sustainably, this being my primary interest in this course.
I come from a political science background with a strong focus on the European Union and would thus find it particularly interesting to analyse and evaluate EU environmental policies with the help of the mainstream and alternative theories that form the core of the module, especially as European environmental policy tends to involve so-called "new modes of governance", implying a shift from hard legislation to other modes of governance as markets or networks. I have a hunge that the theories underlying these new policies still tend to be more on the mainstream site, but it would be interesting to research that properly.