It's been 40 years since we first landed on the moon. More importantly it's been about 37 years since we last landed there. It's time to go back and this time to stay. Not because it's easy, because it's hard. We need the lesson.
When President Kennedy declared that they were going to the moon, they didn't know how they were going to do it. They worked hard, they figured it out, and between the Mercury, Gemini, and Apollo programs they learned a lot.
The technology developed for the moon program didn't just stay in the moon program. It percolated into society in the form of inventions and products that didn't exist before. For instance: Wireless headsets, cordless tools (Black and Decker developed a cordless drill for the Apollo program), memory foam and freeze dried food were all developed to help man land on the moon.
Innovations that we would need to survive long-term on the moon would do more to teach us how to live sustainably than many of the research projects that are going on now. The problem of how to live up there is so hard that it would make us stretch to figure out how to do it, but it would teach us many valuable lessons. These will be things we're not expecting, but things we need to know.
In deciding how to allocate resources in the interest of sustainability, a human colony on the moon certainly makes more sense than spending, for instance, $2 Billion researching Carbon Capture and Storage. That sort of research, even if successful, would keep us addicted to Tar Sands energy, but make us feel slightly less bad about the landscape destruction and carbon intensity of the that dirty fuel.
Going to the moon, combined with the hardcore 'this is all we have' technology that we've learned in developing the international space station will teach us how to live sustainably on earth. For example, water recycling technologies developed for the moon could provide technology to drastically reduce human water consumption. Energy supplies on the moon would be limited, and the energy conservation techniques would be important to long term survival there.
A return to the moon could teach us a lot about how to live on earth.