|Eco-restructuring: Implications for sustainable development (UNU, 1998, 417 pages)|
|Part II: Restructuring sectors and the sectoral balance of the economy|
|8. Global eco-restructuring and technological change in the twenty-first century|
Much of the primary material that passes through the economic system, from automobiles to packaging or sewage pipes, ends up sooner or later as solid waste. There are several emerging rules of thumb for solid waste management: use less material in the first place (i.e. source reduction), re-use products or at least recycle materials to the extent that is practical, and dispose of remaining wastes in a manner that is environmentally benign. It is often necessary to reconceived product design and manufacturing to facilitate recycling, for example by preferring a single material to composites. It is clear that practices in several countries, which have already begun to move in these directions, will spread in the twenty-first century. But these prescriptions are far more complicated than they appear because there are many different ways of proceeding, all of which have different consequences that affect not only a single sector but many parts of an economy. For reasons that have already been discussed in this paper, we can expect a relatively rapid globalization of those solutions that appear to be successful. Then, for better or worse, there will tend to be a "lock-in" (Arthur 1988) on a global scale to these solutions, which will make it hard to replace them by superior ones for many decades to come.
One of the obstacles to the effective recycling of any material is the difficulty of assuring a uniform waste stream of predictable volume. The investment in recycling facilities cannot be justified from a business or from a social point of view unless a steady, reliable source of inputs can be assured. This problem is faced for many materials but none more so than plastics, and they provide an instructive case-study of the challenges for eco-restructuring.
All parties today agree about the need to reduce polymer solid waste in landfills by some combination of source reduction, degradability of the material, and recycling. The problems arise in achieving an appropriate and stable mix because the steps taken to satisfy one objective tend to thwart the other objectives.
One mechanism for source reduction is the substitution of other materials for plastics. However, the most celebrated comparisons, such as McDonald's former polystyrene foam "clamshell" package vs. the replacement of bleached paper/polyethylene wrappers, or disposable vs. cloth diapers, are inconclusive as to their environmental effects - in part because they have not yet been analysed within a sufficiently complete and integrated economy-wide framework. Source reduction can be achieved by lowering consumption; but, after the initial economies, this option is likely to require significant changes in lifestyle that consumers may be reluctant to make. Refilling plastic containers is another option that requires behavioural changes.
Achieving degradability is similarly complicated. Petrochemical based polymers are not intrinsically degradable (Stein 1992, p. 836), and truly degradable ones are still in early stages of commercialization (Luzier 1992, p. 839). Of course, very little of the potential for degradation is actually realized in waste disposal sites designed and managed as landfills rather than composting facilities. Furthermore, the shift in feedstock from hydrocarbons to biomass would have massive implications for the global economy.
A significant problem in the recycling of plastics is the expense of collection and the cost and difficulty of separation even among apparently homogeneous objects and polymers, not to mention objects of mixed composition and composite materials (Stein 1992, pp. 836837). The relative importance of different polymers, and the material composition of many objects, would need to change substantially if large-scale recycling of polymers were to be implemented. Further technical development would be necessary for the separation of mixed plastics (Hegberg et al. 1992, p. 73). Of course, in the unlikely event of a massive substitution away from plastics in many uses, coupled with a reliance on biodegradable plastics, there would be inadequate raw material to justify investing in recycling.
One current prospect is for the development of completely biodegradable polymers from biomass. Polymers derived from starches of annual crops such as corn and potatoes are already in use in several applications such as golf tees and pharmaceutical capsules. A significant programme is also under way to commercialize polymers based on the jute crop of Bangladesh and India; it is hoped that this market will be able to replace the traditional uses of jute, which are lost as polypropylene displaces jute sacks for packaging grain, sugar, fertilizer, and cement (personal communication with Irv Koons, United Nations Development Programme).
Plastics are still displacing other primary materials and paper even in the rich economies, and their use is growing rapidly in developing countries. To the extent that polymers are fabricated from biomass, the demand for the hydrocarbon feedstock is reduced. It could also reduce the solid waste that needs to be disposed of and precipitate the shift from landfills to composting facilities. But it puts pressure back on the land used to grow renewable crops.
The alternative roles that plastics might play in the global economy over the next 50 years may be a particularly fruitful case to study from both a technological and a social and economic point of view. What actually happens, by conscious decision or otherwise, may be only one small contributing factor to the global "big picture," but the range of alternatives that were sketched in the previous few paragraphs demonstrates that although engineering innovation is necessary it is hardly sufficient.