Environmental Problems, Their Causes, and Sustainability 1

SolarenergyChemicalenergy(photosynthesis)Chemicalenergy(food)Mechanicalenergy(moving,thinking,living)WasteheatWasteheatWasteheatWasteheatFigure 3-17 The second law of thermodynamics in action in living systems. Each time energy ischanged from one form to another, some of the initial input of high-quality energy is degraded, usually to lowqualityheat that is dispersed into the environment.stop unnecessarily wasting almost half of the energywe use. We can do this by not driving gas-guzzlingmotor vehicles and by not living in poorly insulatedand leaky houses. What are you doing to reduce yourunnecessary waste of energy?3-8 MATTER AND ENERGY LAWSAND ENVIRONMENTAL PROBLEMSWhat Is a High-Throughput Economy?An Accelerating TreadmillMost of today’s economies increase economicgrowth by converting the world’s resources togoods and services in ways that add large amountsof waste, pollution, and low-quality heat to theenvironment.As a result of the law of conservation of matter and thesecond law of thermodynamics, individual resourceuse automatically adds some waste heat and wastematter to the environment. Most of today’s advancedindustrialized countries have high-throughput (highwaste)economies that attempt to sustain ever-increasingeconomic growth by increasing the one-way flowof matter and energy resources through their economicsystems (Figure 3-18). These resources flowthrough their economies into planetary sinks (air, water,soil, organisms), where pollutants and wastes endup and can accumulate to harmful levels.What happens if more and more people continueto use and waste more and more energy and matter resourcesat an increasing rate? In other words, whathappens if most of the world’s people get infectedwith the affluenza virus?The law of conservation of matter and the twolaws of thermodynamics discussed in this chapter tellus that eventually this consumption will exceed the capacityof the environment to dilute and degrade wastematter and absorb waste heat. However, they do nottell us how close we are to reaching such limits.What Is a Matter-Recycling-and-ReuseEconomy? Go in Circles Instead of StraightLinesRecycling and reusing more of the earth’s matterresources slows down depletion of nonrenewablematter resources and reduces our environmentalimpact.There is a way to slow down the resource use andreduce our environmental impact in a high-throughputeconomy. We can convert such a linear high-throughputeconomy into a circular matter-recycling-and-reuseeconomy that recycles and reuses our matter outputsback instead of dumping them into the environment.Changing to a matter-recycling-and-reuse economyis an important way to buy some time. But thisdoes not allow more and more people to use more andmore resources indefinitely, even if all of them were52 CHAPTER 3 Science, Systems, Matter, and Energy