مقاله سال ۲۰۱۶

Attempting to answer the basic underlying question and concern of sustainability –whether humans are taking more from the earth than the earth can safely yield- is the main objective underlying the concept of dematerialization. Malenbaum (1978) was one of the first researchers in this area and his key results are still among the most important. He utilized the concept of intensity of use defined as the ratio of the amount of materials (or energy) measured in bulk mass divided by GDP. When plotting intensity of use over time, he found “inverted U curves” peaking at different times in different countries (and for different materials) but at roughly a given GDP per capita for given materials. Also importantly, the peak intensity for a given material reached by subsequently developing countries decreases over time (relative to earlier developing countries). These two regularities are the essence of the conceptual basis for the “theory of dematerialization” according to Bernardini and Galli (1993). These authors speculate that the decreasing maximum intensity over time with usage of materials/energy per GDP might be a positive signal of a real dematerializing trend, but they eventually conclude that the empirical information at that time (1993) were insuffi- cient to draw such a conclusion and suggest further examination of data. Given the potential importance of the overall sustainability question, it is not surprising that there has been significant valuable work from the dematerialization perspective (see the next paragraph) and other perspectives, as for instance those claiming the urgent necessity of abating economic growth [the so-called ‘degrowth’ strategy, among whom are differing perspectives such as Knight et al. (2013), Turner (2008), Davidson et al. (2014), and Lamb and Rao (2015)].

From the dematerialization perspective, there has been significant work since Malenbaum. Dematerialization, is often defined as the reduction of the quantity of stuff and or energy needed to produce something useful and is then often assessed by a measure of intensity of use or throughput (consumption/production of energy and/or goods per GDP). Some of this research, Ausubel and Sladovich (1990) and Ausubel and Waggoner (2008), is encouraging emphasizing continuing decreases in consumption as a fraction of GDP. However, other researchers [Ayres (1995), Schaffartzik et al. (2014), Senbel et al. (2003), Schandl and West (2010), are not as encouraging about continuation of economic growth with global dematerialization. Among discouraging papers, Allwood et al. (2011) and especially Gutowski et al. (2013) call for much more attention to reducing the amount of material needed to fulfill a given function (referred to as “materials efficiency”) and point out that decreasing usage of materials as a fraction of GDP is not sustainable unless absolute decreases in materials use occurs. The very recent and extensive work of Pulselli et al. (2015), presents a very interesting 3-dimensional analysis (resources, organization, and products/services) with which the authors scrutinize 99 national economies and conclude that no country is evidencing a dematerialization of economic activity, pointing out also that non-sustainable economic activity can take place over a wide range of income distributions.

There has also been extensive research on a closely related issueusually called the Environmental Kuznets Curve (EKC). The EKC states that emission of pollutants follow a inverted U curve as affluence increases.1 Despite this being a relative and not absolute comparison, the concept was very positively viewed by some starting in the early 1990s [Grossman and Krueger (1991, 1994), IBRD (1992)] as offering the strong possibility that emissions and pollution would not choke off economic growth but that economic growth might instead help eliminate pollution. However, the generality of the EKC has been seriously challenged on empirical, methodological and theoretical grounds [Stern et al. (1996), Stern (2004), Kander (2005)].