This is something I've been thinking about, as a new way of framing the intersection of my interests in well-being and environmental ethics. I'm calling it "An Ecological Paradox of Happiness," although it isn't, strictly speaking, a paradox. (Perhaps I should instead call it the tragedy of happiness, pace Hardin's "tragedy of the commons.")
Consider, for example, the "American Dream" of living comfortably, middle-class, free to move (and fly) where your dreams take you, settling down, having nice things, and so on. (Suppose something like that is the American Dream.) The carbon footprint of the average American is very high; if everyone on the planet lived like the average American, the result would be environmentally unsustainable. Now if more and more people pursue something like the American Dream--read: American happiness--and if more and more countries (e.g. India and China) are industrializing in ways like Western nations (including the United States), then it's obvious we're headed toward insustainability. The more people who pursue and acquire happiness [important caveat: of a certain sort], the more unsustainable global happiness becomes, and the closer we get to ecological disaster, which, of course, will be a cause of great unhappiness for many (future generations).
This leads to something that looks like the traditional paradox of happiness, which says that in order to be happy one must pursue something other than happiness. The ecological version is that it looks like in order to make the happiness of future generations possible, we should pursue something other than (American) happiness, i.e. if we want it to remain possible for future others (as well as others in other parts of the world now!) to live happily, we should give up our own pursuit of happiness.
Now, it seems to me that, to the extent that there is something that seems paradoxical here, it's actually a false paradox, and that, briefly, we don't have to give up happiness (or its pursuit), but instead certain aspects of the "American" part. In connection with this, I just finished a paper by Judith Licthenberg on "Consuming Because Others Consume," which provides some interesting insights on why people consume other than simple greed, particularly in order to maintain a sense of equality to those around them, which for most people, is (according to JL) necessary for self-respect. This is something worth bearing in mind, insofar as her argument makes it clear that the path to sustainable change is going to involve collective action (and policy) rather than exhortations to personal virtue (although that isn't particularly because not enough people are personally virtuous).