Promoting global population health while constraining the environmental footprint.

Populations today face increasing health risks from human-induced regional and global environmental changes and resultant ecological nonsustainability. Localized environmental degradation that has long accompanied population growth, industrialization, and rising consumerism has now acquired a global and often systemic dimension (e.g., climate change, disrupted nitrogen cycling, biodiversity loss). Thus, the economic intensification and technological advances that previously contributed to health gains have now expanded such that humanity's environmental (and ecological) footprint jeopardizes global population health. International data show, in general, a positive correlation of a population's health with level of affluence and size of per-person footprint. Yet, beyond a modest threshold, larger footprints afford negligible health gain and may impair health (e.g., via the rise of obesity). Furthermore, some lower-income countries have attained high levels of health. Many changes now needed to promote ecological (and social) sustainability will benefit local health. Continued improvement of global health could thus coexist with an equitably shared global environmental footprint.