Contenido
Gran parte de la dificultad inherente al reciclaje proviene del hecho de que la mayoría de los productos no están diseñados pensando en el reciclaje. En Estados Unidos, alrededor del 6 al 7 por ciento del plástico se recicla.[24]El concepto de diseño sostenible busca resolver este problema, y fue expuesto en el libro de 2002 De la cuna a la cuna. Rediseñando la forma en que hacemos las cosas, del arquitecto William McDonough y el químico Michael Braungart. Ellos proponen que todo producto (y todo el empaque que requiera) debería tener un ciclo completo de “bucle cerrado” planificado para cada componente: una forma en la que cada parte regrese al ecosistema natural mediante la biodegradación o se recicle indefinidamente.[25][26].
Aunque el reciclaje desvía los desechos para que no entren directamente en los vertederos, el reciclaje actual no recupera los componentes dispersivos. Los críticos creen que el reciclaje completo es impracticable, ya que los desechos altamente dispersos se diluyen tanto que la energía necesaria para su recuperación se vuelve cada vez más excesiva.
Al igual que en la economía ambiental, se debe tener cuidado para garantizar una visión completa de los costos y beneficios involucrados. Por ejemplo, los envases de cartón para productos alimenticios se reciclan más fácilmente que la mayoría de los plásticos, pero son más pesados de transportar y pueden generar más desperdicio por deterioro del producto.[28]Los costos económicos pueden incentivar el fraude.[29].
Net environmental benefits
Critics question the net economic and environmental benefits of recycling compared to its costs, and suggest that recycling advocates often make things worse and suffer from confirmation bias. Specifically, critics argue that the costs and energy used in collection and transportation subtract from (and even exceed) the costs and energy saved in the production process; further, that the jobs created by the recycling industry may not compensate for the jobs lost in logging, mining and other production-related industries; and that materials such as paper pulp can only be recycled a few times before degradation of the material prevents further recycling.[30].
The amount of energy saved through recycling depends on the material being recycled and the type of energy accounting method used. A correct accounting of this saved energy can be achieved through a life cycle analysis using real energy values and, in addition, exergy, which is a measure of how much useful energy can be harnessed. In general, it takes much less energy to produce a unit mass of recycled materials than to produce the same mass of virgin materials.[31][32][33].
Some researchers use emergy analysis, for example budgets, to calculate the amount of energy of one type (exergy) that is required to make or transform things into another type of product or service. Emergy calculations take into account economic factors that can modify purely physics-based results. Using life cycle analysis with emergy, researchers have concluded that materials with high refining costs have the greatest potential to offer large recycling benefits. Furthermore, the highest emergy efficiency is obtained in systems aimed at material recycling, where materials are designed to return to their original form and purpose; followed by adaptive reuse systems, where materials are recycled into a different type of product; and then by-product reuse systems, where parts of the products are used to make a completely different product.[34].
The Energy Information Administration (EIA) states on its website that “a paper mill uses 40% less energy to make paper from recycled paper than to make it from fresh wood.”[35] Some critics argue that it takes more energy to produce recycled products than to dispose of them through traditional landfill methods, since household collection of recyclables often requires a second garbage truck. However, recycling advocates point out that the need for a second logging truck is eliminated when the paper is collected for recycling, so the net energy consumption is the same. A life cycle analysis with emergy on recycling revealed that fly ash, aluminum, recycled concrete aggregate, recycled plastic and steel have the highest efficiency rates, while wood recycling generates the lowest benefit ratio. Therefore, the specific nature of the recycling process, the methods used to analyze it and the products involved influence energy savings budgets.[34].
It is difficult to determine the amount of energy consumed or produced in waste disposal processes in broader ecological terms, where causal relationships dissipate into complex networks of material and energy flow.
The amount of energy used in recycling also depends on the type of material being recycled and the process used to do so. It is generally accepted that aluminum consumes much less energy when recycled than when produced from scratch. The EPA states that “recycling aluminum cans, for example, saves 95% of the energy needed to produce the same amount of aluminum from its virgin source, bauxite.”[37][38]In 2009, more than half of all aluminum cans produced came from recycled aluminum.[39]Similarly, new steel produced from recycled cans has been estimated to reduce greenhouse gas emissions by 75%. %.[40].
Economist Steven Landsburg has suggested that the sole benefit of reducing landfill space is outweighed by the energy required and pollution resulting from the recycling process.[42] However, others have calculated through life cycle assessment that producing recycled paper uses less energy and water than harvesting, pulping, processing and transporting virgin trees. When less recycled paper is used, additional energy is needed to create and maintain cultivated forests until they are as self-sustaining as virgin forests.
Other studies have shown that recycling itself is inefficient in achieving the “decoupling” of economic development from the depletion of non-renewable raw materials, necessary for sustainable development.[43]International flows of transportation or recycling of materials through “…different trade networks of the three countries result in different flows, degradation rates and potential recycling returns.”[44]As global consumption of natural resources grows, their depletion is inevitable. The most recycling can do is delay it; The complete closure of material cycles to achieve 100% recycling of non-renewables is impossible, as micro-materials disperse into the environment causing severe damage to the planet's ecosystems.[45][46][47]Historically, this was identified as metabolic breakdown by Karl Marx, who noted the unequal exchange rate between energy and nutrients that flow from rural areas to feed urban cities, generating waste that degrades the ecological capital of the planet, such as the loss of nutrient production in the soil.[48][49]Energy conservation also leads to what is known as the Jevons paradox, where improvements in energy efficiency reduce the cost of production and cause a rebound effect, increasing consumption rates and economic growth.[47][50].