What is wellbeing? Depends on how one defines and measures it. With the inadequacy of GDP as a measure on well-being, alternative measures are developed. These measures, however, are at risk of not bridging the debate between economic, ecological and social aspects of well-being, but of reinforcing the differences in worldviews between respective disciplines.
For example, Africa's ecological footprint are the lowest in the world (with the notable exceptions of Libya and South Africa), but they continue to have low quality of life (as measured through the HDI). This is neatly illustrated by the following figures from a publication on Africa's ecological footprint by the Global Footprint Network.
Measuring well-being first needs an alternative to the simple aggregations of individual economic utility. Kahneman's proposal to distinguish among different conceptions of utility rather than presume to measure a single, unifying concept that motivates all human choices and registers all relevant feelings and experiences, looks promising.
Secondly, given that socio-ecological systems do operate under thresholds, and given that the risks of breaching these thresholds does not filter into measures of subjective well being, it will make sense to develop indicators that indicate larger-scale thresholds and limits.
For an interesting set of presentations on the measurement of sustainability see this symposium held at the Sydney University.
In summary, we need a dual strategy of digging deeper in the human psyche and broader into the Earth's thresholds to improve understanding and measurements of wellbeing.