Technological Trajectories and the Human Environment (1997) / Chapter Skim
Currently Skimming:
Materialization and Dematerialization: Measures and Trends
Materialization and Dematerialization: Measures and Trends
Pages 135-156
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 135... ...
Lower materials intensity of the economy could reduce the amount of garbage produced, limit human exposures to hazardous materials, and conserve landscapes. From time to time, fears arise that humanity will imminently exhaust both its material and energy resources.
|
From page 136... ...
The macroscopic picture of materialization can help raise key research questions and set priorities among the numerous studies of materials flows and networks that might be undertaken. It puts these in a dynamic context of both technical and market change.
|
From page 137... ...
Percentage of Total Moles Elements and Compounds 1968 1990 Hydrocarbons 83.20 86.77 Silicon dioxide 12.33 9.35 Iron 1.30 0.64 Oxygen 0.61 0.76 Sodium 0.s7 0.44 Chlorine 0.57 0.44 Nitrogen 0.47 0.67 Phosphorus 0.29 0.35 Sulfur 0.21 0.25 Calcium carbonate 0.15 0.10 Aluminum 0.15 0.13 Potassium 0.09 0.07 Copper 0.04 0.02 Zinc 0.02 0.01 Lead 0.005 0~004 Magnesium 0.004 0.003 SOURCES: Chemical Manufacturers Association (1991) , US Bureau of the Census (1975, 1992)
|
From page 138... ...
Materials in this category may be associated with local environmental issues as excavations and structures transform the landscape, for better or worse. A striking fact is that 30 percent of the industrial minerals consumed dissipated into the environment and thus were rendered practically unrecoverable.
|
From page 139... ...
Aluminum Steel Copper Silver Lead Mercury Gold Platinum Osmium .00 1.06 1.7-2.0 2.3 2.7 2.~2.8 2.8 2.7 7.8 8.9 10.5 11.3 13.6 19.3 21.4 22.5 SOURCES: Giancoli (1988) and Handbook of Chemistry and Physzcs (1962)
|
From page 140... ...
For plastics we use production data only. DATA SOURCES: Modern Plastics (1960J; US production of plastics resin, personal communication with Joel Broyhill, Statistics Department, Society of the Plastics Industry, Washington, D.C., August 20, 1993; US Bureau of the Census (1975, 1991, 1992, 1993, 1994, 19951; and US Bureau of Mines (venous years)
|
From page 141... ...
But, as Figure 2 also shows, paper consumption per unit of GNP has stayed essentially flat since 1930. Dunng World War II, Amenca briefly and drastically reduced its paper use relative to GNP or, rather, increased GNP without increas .
|
From page 142... ...
FIGURE 3 US per capita volumetric material consumption for wood/plywood products, paper/paper products, plastic, and metals plotted against GNP per capita in constant 1990 dollars. NOTE: Volume is calculated from average material densities.
|
From page 143... ...
Cars have also become lighter on average, although the recent sales growth of light trucks and sport vehicles counters this trend. The car is an interesting object for study because it represents a full market basket of the products of an industrialized economy, including metals, plastics, electronic materials, rubber,
|
From page 144... ...
Although aircraft use a tiny fraction of all materials, the aerospace sector, where performance demands are exceptionally stringent, has foreshadowed trends that later appear in the rest of the economy. The drive to downmass aircraft while improving their performance has placed the aerospace industry at the forefront of materials research.
|
From page 145... ...
In the late 1980s, platinum prices needed to exceed $500 an ounce to make platinum recovery from catalytic converters economical (Frosch and Gallopoulos, 1989~. Energy prices can spark secondary materials recovery trends in opposite directions.
|
From page 146... ...
For example, suppliers of virgin materials can adjust their prices to undercut recycled supplies. Economic and population growth, of course, tend to draw new materials into the system.
|
From page 147... ...
NOTE: Data records for all single-family dwellings built during the period 1945-1990 in twentyfive of the twenty-nine zip codes within the Austin metropolitan area were used. DATA SOURCE: Austin Multiple Listing Service, Inc.
|
From page 148... ...
This hypothesis should be treated with caution because it combines national aggregate data with data only for the city of Austin. The trend toward larger floor areas housing fewer people implies that our consumption of building materials on a per capita basis is increasing, as is our requirement for energy services such as heating and cooling (see Schipper, this volume)
|
From page 149... ...
The average load increased by almost 20 percent to 3,050 kg (about a sixty-day stock of accumulated materials at the American rate of 50 kg/day) from 1977 to 1991 (personal communication from George Bennett, Statistics Department, Household Goods Carriers Bureau, Alexandria, Va., October 14, 1993~.
|
From page 150... ...
Medical Coal Ash Municipal Solid Waste Hazardous ~/~///~1 Agri /////////,/ Oil and Gas ace//////////: Mining Manufacturing ~././///////////////./././//.///././//.///././/.////./////.//./././/-////-/-/-//////-/////-/////: 1 0 1 2 3 4 5 6 Billion Metric Tons of Waste Generated FIGURE 8 Major waste types by weight in the United States, 1985. NOTE: A large fraction of the total weight in the industrial categories is water.
|
From page 151... ...
While MSW increased by about 1.5 percent per capita annually in the United States between 1960 and 1993, the amount of American trash generated per unit of GNP decreased, or dematerialized, on average by about 0.3 percent per year despite a recent upturn (Figure 9~. As shown in Figure 10, reported waste generation varies markedly by country.
|
From page 152... ...
The first part of their theory is that new materials substitute for old in subsequent periods of time (Fisher and Pry, 1971) , and each new material shows improved physical properties per unit quantity, thus leading to a lower intensity of use.
|
From page 153... ...
With regard to primary materials, summary ratios of the weight of materials used to economic product appear to be decreasing due to materials substitution, efficiencies, and other economic factors. The tendency is to use more scientifically selected and often artificially structured materials (Sousa, 1992~.
|
From page 154... ...
In general, viewing the environmental impact of a product in isolation from the total system is simplistic. For example, examined in isolation, a computer could be deemed environmentally unfriendly because the production of the printed circuit boards, logic and memory chips, and display screens requires a large quantity of hazardous chemicals and solvents and heavy metals.
|
From page 155... ...
We also thank the Austin Multiple Listing Service, Inc. and Boons Systems for providing access to their database of Austin residences.
|
From page 156... ...
1994. Dematerialization and secondary materials recovery: A long-run perspective.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.