Mapping the Carbon Footprint of Nations

Life
cycle thinking asks companies and consumers to take responsibility
for emissions along their entire supply chain. As the world economy
becomes more complex it is increasingly difficult to connect consumers
and other downstream users to the origins of their greenhouse gas
(GHG) emissions. Given the important role of subnational entitiescities,
states, and companiesin GHG abatement efforts, it would be
advantageous to better link downstream users to facilities and regulators
who control primary emissions. We present a new spatially explicit
carbon footprint method for establishing such connections. We find
that for most developed countries the carbon footprint has diluted
and spread: for example, since 1970 the U.S. carbon footprint has
grown 23% territorially, and 38% in consumption-based terms, but nearly
200% in spatial extent (i.e., the minimum area needed to contain 90%
of emissions). The rapidly growing carbon footprints of China and
India, however, do not show such a spatial expansion of their consumption
footprints in spite of their increasing participation in the world
economy. In their case, urbanization concentrates domestic pollution
and this offsets the increasing importance of imports.