High School Earth Science/Use and Conservation of Resources

In the Monongahela National Forest of West Virginia (Figure 20.1), scientists have a mystery to solve: the mystery of the missing plant nutrients, which are substances in the soil that plants need to grow. For several years, the trees there have not grown as well as they should. Soil scientists believe that the soil is missing many of the important nutrients that the trees and other plants there need to grow. They have conducted many years of research to determine why the nutrients are disappearing and why the trees are not growing like they should.

**Figure 20.1**: The Monongahela National Forest in West Virginia supplies us with many natural resources, including, timber, wildlife, coal, gas, recreation, and fishing.

Mary Lusk was one of the soil scientists who worked to solve the mystery of the missing nutrients in the forest. She gathered samples of the soil and tested it for important nutrients. She saw that the soil has very low levels of plant nutrients, such as magnesium and calcium. If these nutrients are not in the soil, the trees cannot grow well. She wondered why the soil had such low levels of these nutrients. After a little more research, she developed the hypothesis that air pollution from nearby factories has been putting chemicals in the environment that are removing the nutrients from the soil. In a sense, the pollution is "snatching" the nutrients and carrying them out of the soil.

Scientists in the Monongahela National Forest are still researching the missing plant nutrients. They are trying to learn what they can do to help keep the nutrients in the soil, so the trees will grow better. The forest is an important natural resource. A natural resource is something from nature that we depend on. We depend on the Monongahela National Forest for many reasons, including:

Recreation, such as hiking, camping, and picnics.
The forest is vital habitat for many animals, including 9 endangered species and 50 different species of rare plants.
The forest contains 207 kilometers (129 miles) of streams for fishing, particularly trout fishing.
Hunters use the forest for hunting deer, squirrels, turkeys, rabbits, mink, and foxes.
The forest contains materials that we use, such as coal, gas, limestone, and gravel.
The forest has abundant hardwood trees used for timber, which is sold for over 7 million dollars a year.

Like the Monongahela National Forest, we use many parts of the Earth for many reasons (Figure 20.2). We depend on materials from the Earth for food, water, building materials, timber, recreation, and energy. However, human activities can degrade these natural resources, just like air pollution from factories is speeding up the loss of soil nutrients in West Virginia (Figure 20.3). We need to conserve our natural resources so they will always be around. When we practice conservation, we make sure resources will be available in the future, both for ourselves and for other organisms.

Lesson Objectives

Discuss some natural resources used to make common objects.
Describe some ways to conserve natural resources.

Renewable versus Non-renewable Resources

Natural resources may be classified as renewable or non-renewable. Renewable resources are those that can be regenerated, which means new materials can be made or grown again at the same rate as they are being used. For example, trees are a renewable resource because new trees can be grown to replace trees that are cut down for use. Other examples of renewable resources include soil, wildlife, and water. However, some resources, like soil, have very slow rates of renewal, so we still need to conserve them. It is also important to realize that while these resources are in most cases renewable, we can still pollute them, damage them or over-use them to the point that they are not fit for use anymore. Fish are considered a renewable resource because we can take some fish but leave others to reproduce and create new fish for later use. Imagine, however, what can happen if we over-fish, or take too many fish at one time. If we over-harvest our trees or wildlife resources, we may not leave enough to let the resource renew itself.

Non-renewable resources are resources that renew themselves at such slow rates that, practically, they cannot be regenerated. Once we use them up, they are gone for good—or at least for a very, very long time. Coal, oil, natural gas and minerals are non-renewable resources. It takes millions of years for these materials to form, so if we use them to the point of depletion, new resources will not be made for millions more years. We can run out of these resources.

Common Materials We Use From the Earth

What do a CD, a car, a book, a soda can, a bowl of cereal, and the electricity in your home all have in common? They are all made using natural resources. For example, a CD and a soda can are made of metals that we mine from the Earth. A bowl of cereal comes from wheat, corn, or rice that we grow in the soil. The milk on the cereal comes from cows that graze on fields of grass. We depend on natural resources for just about everything that we eat and use to keep us alive, as well as the things that we use for recreation and luxury. In the United States, every person uses about 20,000 kilograms (40,000 pounds) of minerals every year for a wide range of products such as cell phones, TVs, jewelry, and cars. Table 20.1 shows some common objects, the materials they are made from and whether they are renewable or non-renewable.

Table 20.1: Objects and Their Required Resources
Common Object	Natural Resources Used	Are These Resources Renewable or Non-renewable?
Cars	15 different metals, such as iron, lead, and chromium to make the body	Non-renewable
Jewelry	Precious metals like gold, silver, and platinum; gems like diamonds, rubies, emeralds, turquoise	Non-renewable
Electronic appliances (TVs, computers, DVD players, cell phones, etc.	Many different metals like copper, mercury, gold	Non-renewable
Clothing	Soil to grow fibers such as cotton; sunlight for the plants to grow; animals for the fur and leather	Renewable
Food	Soil to grow plants; wildlife and agricultural animals	Renewable
Bottled water	Water from streams or springs; petroleum products to make plastic bottles	Non-renewable and renewable
Fuel	Petroleum drilled from wells	Non-renewable
Household electricity	Coal, natural gas, solar power, wind power, hydroelectric power	Non-renewable and renewable
Paper	Trees, sunlight, soil	Renewable
Houses	Trees for timber; rocks and minerals for construction materials, for example; granite, gravel, sand	Non-renewable and renewable

Human Population and Resource Use

As the human population grows, so does the use of our natural resources. A growing population creates a demand for more food, more clothing, more houses and cars, etc. Population growth puts a strain on natural resources. For example, nearly 500 people move into the Tampa, Florida area every week (Figure 20.4). Tampa's population is growing quickly. The Tampa area may have over 3 million people by 2010. One of Tampa's rivers, the Hillsborough River, is pumped for drinking water to support all the people. Too much water is being taken from the river. The river is becoming salty, as water from the nearby Gulf of Mexico starts to take the place of the freshwater being pumped out. This hurts wildlife and may eventually make the river water unsuitable for human use. Many other examples like this are taking place worldwide.

Figure 20.4: Downtown Tampa, Florida is growing at an enormous rate. The growing human population puts a strain on natural resources, like rivers and other bodies of water.

Resource Availability

You can see from the table above that many of the resources we depend on are non-renewable. We will not be able to keep taking them from the Earth forever. Also, non-renewable resources vary in their availability. Some are very abundant and others are rare. Precious gems, like diamonds and rubies, are valuable in part because they are so rare. They are found only in small areas of the world. Other materials, like gravel or sand are easily located and used. Whether a resource is rare or abundant, what really determines its value is how easy it is to get to it and take it from the Earth. If a resource is buried too deep in the Earth or is somehow too difficult to get, then we don’t use it as much. For example, the oceans are filled with an abundant supply of water, but it is too salty for drinking and it is difficult to get the salt out, so we do not use it for most of our water needs.

Resource availability also varies greatly among different countries of the world. For example, 11 countries (Algeria, Indonesia, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, the United Arab Emirates, and Venezuela) have nearly 80% of all the world's oil (Figure 20.5). However, none of these is the world's biggest user of oil. In fact, the biggest users of oil, the United States, China, and Japan, are all located outside this oil-rich region. This difference in availability and use of resources can be a source of economic and political trouble throughout the world. Nations that have abundant resources often export them to other countries, while countries that lack a resource must import it from somewhere else.

Figure 20.5: The nations in green are the biggest producers of worldwide oil. They have almost 80% of the world's current oil supply, even though the United States, China, and Japan are the world's biggest users of oil.

In developed countries like the United States and most of Europe, we often use many more natural resources than we need just to live. We have many luxury and recreational materials made from resources. We also tend to throw things away quickly because we can afford to replace them. Discarding materials not only leads to more resource use, but it also leads to more waste that has to be disposed of in some way. Pollution from discarded materials degrades the land, air, and water (Figure 20.6). As our cities and neighborhoods grow, we use more and more resources and produce more and more waste. Natural resource use is generally lower in developing countries because people cannot afford to use as much. Still, developing countries need to actively protect their resources by adopting sustainable practices as they develop.

Figure 20.6: Pollution from discarded materials degrades the environment and reduces the availability of natural resources.

Conserving Natural Resources

We need to conserve natural resources so that we can continue to use them in the future, and so that they will be safe for use. While renewable resources will not run out, they can become degraded or polluted. For example, water is a renewable resource, but we can pollute it to the point that it is not safe for use. Reducing use and recycling materials is a great way to conserve resources (Figure 20.7). Many people are also researching ways to find renewable alternatives to non-renewable resources. Here is a checklist of some things we can do to conserve resources:

Purchase less stuff (use items as long as you can, ask yourself if you really need something new.)
Reduce excess packaging (for example, drink water from the tap instead of buying it in plastic bottles).
Recycle materials like metal cans, old cell phones, and plastic bottles.
Purchase products made from recycled materials.
Keep air and water clean by not polluting in the environment.
Prevent soil erosion.
Plant new trees to replace ones that we cut down.
Drive cars less, take public transportation, bicycle, or walk.
Conserve energy at home (for example, by turning out lights when they are not needed).

Figure 20.7: Recycling can help conserve natural resources.

Lesson Summary

We use natural resources for many things. Natural resources give us food, water, recreation, energy, building materials, and luxury items.
Many resources vary in their availability throughout the world. Some are rare, difficult to get or in short supply.
We need to conserve our natural resources, protecting them from pollution and overuse.
We can use materials less or recycle to conserve resources.
We can also make efforts to reduce pollution and soil erosion in order to conserve resources.

Review Questions

List five general things we get from natural resources.
We depend on forests as habitat for wildlife. How does this make a forest an important resource for people?
How could human life be affected if a large amount of soil erosion affected our soil resources?
How does discarding products lead to more resource use?
How does choosing to walk or ride a bicycle instead of riding in a car help conserve resources?

Vocabulary

conserve: To keep things safe and ensure that they will always be around.
export: To send out to another country.
import: To receive from another country.
non-renewable: A resource that cannot be regenerated; once it is used up, it cannot be replaced within a human lifetime.
timber: Trees that are cut for wood to be used for building or some other purpose.
nutrients: Substances that a living thing needs to grow.
renewable: A resource that can be regenerated, new ones can be made or grown to replace ones that get used.

Points to Consider

Could a renewable resource ever become nonrenewable? How?
How many resources do you use every day?
Which is more sustainable: using renewable resources or nonrenewable resources? Why?

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