On not finding a useful image

Posted on August 15, 2011


I’ve spent the day looking in vain for visual representations of Commoner/Ehrlich/Holdren’s IPAT equation:

Impact on the Planet = Population  X  Affluence  X  Technology (IPAT) or I = P * A * T

or in words:

Environmental degradation = population × consumption per person × damage per unit of consumption

Ray Anderson argued that equation is not immutable.   If we could move technology to a demoninator – ie  renewable, recyclable materials or renewable energy – the impact is reduced.    Then Anderson argued that if we converted “A” to “a”, signifying affluence to be a means to an end, and not the end in itself.  This he described as a “revised impact equation”:  More happiness with less stuff, all made sustainably.

The lowest impact technologies, those that are beneficial, (belong in the denominator), should grow.  The abusive “numerator technologies” should shrink and eventually disappear.  The sale of services should grow.  The sale of products should shrink.  Applied brainpower should grow.  Applied brute force should shrink.  Market shares for the sustainable companies should grow.  For the unsustainable companies, market shares should shrink—to zero.

Useful things in passing:


http://www.4thtransition.ws/index.php/reflection/models/i-pat/ (ecological footprint is analogous concept)

http://dieoff.org/page111.htm Dietz and Rosa examine historical context and reformulation of each of the IPAT elements  (T technology in particular needs elucidation). . Argues that IPAT a useful starting point as a  theoretical framework to conceptualize human-environment interactions.



http://www.ipat-s.org/IPAT_and_ImPACT.html IPAT-S scenario  model-building language scripting language takes the IPAT formula as a starting point.

Waggoner and Ausubel(2002) renovate IPAT to ImPACT:

Population, income, consumers’ behavior, and producers’ efficiency jointly force impact. Here, we renovate the ‘‘IPAT Identity’’ to identify actors with the forces. Population, income, consumers’ behavior, and producers’ efficiency jointly force impact. Here, we renovate the ‘‘IPAT Identity’’ to identify actors with the forces. Forcing impact I are P for population, A for income as gross domestic product (GDP) per capita, C for intensity of use as a good per GDP, and T for efficiency ratios as impact per good.

C and c. Intensity of use, such as energy per GDP. Consumers lever C as they decide to employ more or less of their economic muscle on the product that will eventually impact the environment. We define dematerialization, or resource sparing by consumer behavior, as a declining C and so negative c.

These definitions assembled into the framework called ImPACT can organize the accretion of definitions and dimensions that IPAT has collected since it emerged a generation ago. A goal is finding which actor has leverage for lessening environmental impact

ImPACT simply shows changing environmental impact means changing four multiplying forces: the number of people, the economic muscle of each, the fraction of economic activity devoted to a good, and the impact of making the good. Consumers can lessen impact by using lever C, and producers can lessen impact by innovating with lever T. Dematerialization is declining C, and efficiency is declining T

Stern (1997) consumption as a problem for environmental science; environmental impacts of consumption