Unit 7: Resources and the Environment Chapter 27: Human Impact on Earth Resources     Human Impact on Earth Resources How much does a hamburger cost? The price you pay for a hamburger at your favorite fast-food restaurant doesn’t reflect the true environmental cost of raising, transporting, and producing the grain-fed beef inside the bun. Imagine what the true cost would be if all the resources used to make the tomatoes, pickles, catsup, mustard, and lettuce inside the bun was also taken into account. True Costs of Resource Use Everything you do impacts the environment because you are a living thing. However, much of your impact on the environment is hidden from you. For example, production of a pair of sneakers has a global environmental impact. An American shoe company designs the shoes, and the leather for the upper shoes comes mostly from cows raised in Texas. The spongy midsole and the synthetic rubber tread of the shoe are composed of materials manufactured from Middle Eastern petroleum. The shoes are assembled in an Asian shoe factory, then packaged in a box manufactured in the United States, and transported across the Pacific Ocean in a ship powered by fossil fuels. After the shoes wear out, they are usually thrown in the trash and ultimately buried in a landfill. And you thought you were only throwing out a pair of sneakers! As more and more people become aware of the environmental impact of their actions, questions are now being asked about resource use. What is the total environmental cost of developing and using a resource? How will it affect the quality of human life? Do the benefits of using a resource outweigh any negative environmental impacts? When answering these questions, it’s important to remember that other species also require resources to exist. The issue for humans is how to balance the conflicting needs for resources with the maintenance of healthy ecosystems. The reality of a sustainable society depends upon achieving this balance. A sustainable society is one that manages its resource consumption and minimizes environmental impacts so that the quality of life is maintained. The current rate of resource consumption in the United States does not appear to be sustainable. The United States includes only 4.5 percent of the world’s population, and yet it consumes more than 25 percent of the world’s energy resources. As developing countries increase their demands for resources, there soon may not be enough to go around. Percentage of Worldwide Resources Consumed by the United States Resource % of Total Amount Used in United States Aluminum 27 Copper 25 Steel 13 Oil 27 Natural Gas 28 LINK-UP: Find out more information about global resource use. What can be done to conserve resources and minimize the environmental impacts caused by using Earth’s resources? In addition to solving problems that were created by past practices, humans need to prevent any additional negative impacts. This can be done, in part, by reducing, reusing, and recycling resources. Reduce Reducing the use of resources is one way to minimize negative impacts on Earth’s systems. For example, reducing the amount of electricity consumed by appliances such as refrigerators, televisions, and lightbulbs will decrease the amount of oil and coal burned by power plants, which in turn, will decrease the amount of harmful gases released into the atmosphere. Increasing the fuel efficiency of automobiles is another way to reduce both air pollution and the demand for oil. New hybrid automobiles use combinations of electric motors, batteries, and small gasoline engines to achieve a fuel efficiency of 30 km/L or more. Reducing the amount of material used in manufacturing and packaging also can minimize the use of resources. For example, the aluminum cans produced today contain less aluminum than cans produced a decade ago. Manufacturers have also reduced the amount of plastic in 2-L soda bottles. Modern automobiles contain more aluminum, more fiberglass, and less steel than those produced in the past, so their overall mass is less, which improves their fuel efficiency. Reducing excess packaging is another way in which resources as well as landfill space can be saved. Reuse Waste materials such as sewage wastewater can often be reused. The figure below shows how some cities are reusing sewage wastewater and reducing both water pollution and water consumption. Building materials also can be reused after the remodeling or demolition of existing structures. Lumber, plumbing fixtures, wires, and other hardware can be salvaged from buildings and sold. In some areas, there is a high demand for antique fixtures from older buildings. Many older cities now have programs that provide financial incentives for people to fix up older homes rather than build new ones. Recycle Recycling is another way to stretch the availability of resources. For example, the recycling of paper saves forest habitats by reducing the number of trees that are cut down for wood pulp. This in turn reduces the pollution generated by paper mills, and it also saves landfill space. The table below shows the amounts of various materials that are currently being recycled in the United States. Materials Recycled in the United States (1997) Material Million tons recycled % of total generated Paper, cardboard 35 42 Ferrous metals 4.7 38 Aluminum 1.1 35 Other metals 0.8 65 Glass 2.9 24 Plastic 1.1 5 Yard wastes 11.5 41 Other wastes 3.8 7 Total material recovered from waste stream 60.8 28 For recycling to work effectively, there must be a market for recycled materials. If there is no demand for recycled materials, then there is no incentive for companies to use them. Creating incentives for companies to use recycled materials is often referred to as "closing the loop." Consumers must be willing to purchase items that contain recycled material, such as paper towels and napkins. Although recycled materials can be more expensive than new ones, educated consumers know that the extra cost is well worth the benefit to the environment. Activity Even after treatment, sewage wastewater still contains nutrients in the form of nitrogen and phosphorus. As a group, research how a city might reduce the amount of excess nutrients that enter wetland areas. Develop a proposal to present to your class. Then, as a class, discuss the merits of each group’s proposal.