Unbridled consumerism in developed nations, marked by increased use of
environmental resources, competes with escalating population growth i
n developing nations as principal threats to environmental sustainabil
ity. The paper examines the issue of sustainability through the I = P
X A X T identity, whereby the impact of any population or nation on en
vironmental sources and sinks is a product of its population, its leve
l of affluence, and the damage done by the technologies that support t
hat affluence. Population stabilization is essential in the transition
towards sustainability. Likewise, reduced consumption, poverty allevi
ation and improved management of environmental resources are key in th
is transition. Finally, technology transfers to low-income nations are
vital in reducing environment throughput. In closing, the article out
lines priorities for high- and low-income nations alike, pointing out
that changes in public perceptions about the concept of development ar
e needed to avoid overshooting the carrying capacity of the Earth.