I am wondering if there is any evidence that happy people (i.e. generally satisfied with their life condition) live more sustainable (i.e. have a lower environmental footprint) than unhappy people.
The largest predictor of sustainable consumption is poverty. The diverse rich all consume far more resources. Because there is a robust relationship between income and health, and even between income and happiness, I would expect that across large populations the happiest are behaving less sustainably.
The environmental behavior of rich countries affects poor countries much more than the reverse, even given the much lower population of rich countries: https://www.telegraph.co.uk/news/science/science-news/3322505/Environment-damage-of-rich-countries-on-poor.html
Happiness increases linearly with income, and then plateaus https://qz.com/1211957/how-much-money-do-people-need-to-be-happy/