Sizing the earth: Recognition of economic carrying capacity

Abstract

Abstract This paper argues that the biophysical properties of a finite earth and the realities of economic transformation determine the economic carrying capacity of our planet. Economic carrying capacity takes the form of maximum global economic welfare derivable from the sustainable throughput flows of the ecosphere. This is fleshed out by development of a welfare return curve plotted as a function of economic scale; the latter is measured by entropic throughput. The economic-ecological connection is made by employing the Ehrlichs' equation, PAT = Impact, as the dual entity being measured on the abscissa. This curve shows an initial acceleration which eventually flattens, reaches a maximum (carrying capacity) and is followed by declining welfare. The shape of this curve is determined by the rising costs associated with the ecosystemic impact of increasing throughput rates as required by a growing economy. The primary thrust of the argument is that not only are economic scales that exceed throughput sustainability definitionally impossible to maintain in the long run, but because of declining welfare, they are not even desirable in the short run. Historical movement along this curve is discussed, reflecting growth in the global economy. An analysis of rising impact costs and the serious mistake of advocating growth to meet these costs is given, employing the notion of a social trap. Also investigated are several additional causes and likely results of pending economic overshoot. Among these are inter-generational penalties of reduced welfare potential from a planet degraded by economic overgrowth. Several overshoot avoidance prescriptions are offered as well as a discussion of stasis and contraction.