Earth's Systems: Natural resources

Transcription

1 Earth's Systems: Natural resources By Encyclopaedia Britannica, adapted by Newsela staff on Word Count 764 Level MAX Water, a renewable resource, gushes from a spring in Brazil. Photo by: Jonathan Wilkins. A natural resource is any material, substance or organism found in nature that is useful to people. Some natural resources are necessary for life. Others have economic value and contribute to industry. Air, water, soil, wildlife, forests, minerals and fossil fuels are among the most familiar of Earth s natural resources. Most natural resources are not distributed evenly around the Earth. For example, some areas have abundant water, while other places may be arid or prone to drought. Countries that are richly endowed with natural resources have an economic advantage. They can sell those resources to other countries. For example, countries with large forests generally are major exporters of wood, paper and paper products. Natural resources can be described as either renewable or nonrenewable based on whether they can be replaced in nature after they are used. Wood is an example of a renewable resource. After a tree is harvested, a new tree can be planted to replace it. In contrast, metals are nonrenewable resources. When a metal such as copper is mined, it cannot be replaced. This article is available at 5 reading levels at 1

2 Renewable Resources A renewable resource is a natural resource that cannot be used up. Air, water, soil, plants and animals are examples of renewable resources. Nearly all living things need air, making this one of the most essential natural resources. Air surrounds Earth as the atmosphere. However, though air is limitless in supply, air quality is a problem in many parts of the world because of pollution. Water is one of the most important natural resources. All living things need fresh water to survive. Most organisms can live for weeks without food but only days without water. However, only about 3 percent of Earth s water is fresh water. Of this, only a tiny fraction is surface water, the water used by living things. Fresh water is not uniformly distributed around the world, and its availability strongly affects where and how organisms live. Getting enough This article is available at 5 reading levels at 2

3 fresh water is a serious problem in many places. Water pollution is a global problem affecting even areas with an abundant water supply. Thus, while water is a renewable resource, the supply of fresh surface water is limited in some places. Although it cannot be used for drinking, salt water also is an important natural resource. The water in oceans, estuaries and saline wetlands is a vital part of those ecosystems. Pollution, oil spills and other disturbances of these areas can disrupt food chains and destroy plant and wildlife populations. Like air and water, soil is necessary to life on Earth. Soil provides water and nutrients for plants and soil-dwelling organisms such as bacteria, worms and fungi. Soil supplies a medium for filtering and breaking down wastes. It also plays a critical role in cycling carbon and other elements through Earth s systems. Plants and animals are also renewable resources. Normally living things replace themselves through reproduction. But such human activities as hunting, logging, building and polluting can cause whole groups of living things to disappear forever. This article is available at 5 reading levels at 3

4 Nonrenewable Resources Nonrenewable resources are natural resources that cannot be replaced after they are used. This means that they exist in a fixed amount on Earth. Rock, minerals, metals, uranium and fossil fuels such as petroleum, coal and natural gas are all nonrenewable resources. Fossil fuels are so-named because they formed from the buried remains of ancient plants and animals over millions of years. Coal and liquid petroleum (oil) are used to generate electricity in power plants around the world. Oil and gasoline provide fuel for heating and operating machinery and motor vehicles. Petroleum is a source of chemicals used to make plastics, synthetic fabrics, medicines and other products. Natural gas is used for heating and cooking. This article is available at 5 reading levels at 4

5 Rocks, minerals and metals are found within Earth s crust. Rocks are removed by quarrying; minerals and metals must be removed by mining. Rocks provide materials for building homes and roads. Minerals and metals are used for manufacturing products. These range from household products to paints, pipes and other building supplies, computer chips, and more. What Humans Do To Natural Resources Many people fear that humans are destroying the world s natural resources. Clearing land for farming and building wipes out forests and the animals that live there. Cars and factories use huge amounts of oil every day. They also release poisonous chemicals that pollute the air, water and soil. Many people are working to conserve, or protect, natural resources. In addition, scientists are working on ways to produce energy and goods without causing pollution or using up valuable natural resources. This article is available at 5 reading levels at 5