Worldwide sustainable happiness is possible.
If we define happiness as the absence of pain and suffering, and we allow for natural ebbs and flows, happiness could easily be sustainable.
There will always be times of pain and suffering. This is part of life.
Happiness is in part a perception of reality.
Change global perceptions, and achieve global happiness.
Even with every need met, happiness is often not achieved. At the same time, a dying person with little of their needs being met can be happy. It is a matter of perception.
Here is a link that describes some keys to happiness -
http://www.livescience.com/health/060227_happiness_keys.htmlImagine if you will what a world would look like where happiness is coveted more then money, power, and sex. In this world happiness would be sustainable.
How would it affect US interests? It would destroy US interests and transform our interests into something available to all, not just the privileged.