Witkins rightly argues that population may be deemed a valid sustainable development indicator—that sustainability can only be implemented by limiting population below the carrying capacity of the Earth. This thesis works relatively well when one presupposes that global per capita consumption is homogenous, (5) and that the global ecosystem can perform. with uniform. effectiveness the tasks of supplying resources and assimilating wastes, but in reality population effects vary widely due to vast regional differences in ecosystem characteristics. While large populations exert considerable stress on their ecosystems, small populations with high rates of consumption can eclipse the effect of larger (10) populations operating at lower rates of consumption. Per capita consumption of energy may exponentially exceed the physiological energy requirements of humans, requiring that both population and consumption be taken into account. Witkins thus ignores the corollary that the impact of population tends to be more significant on a national level than that of consumption adjusted population, but (15) on a global level, the opposite obtains. The passage supplies information that would answer which of the following questions?