How Do Humans Impact Their Environment?

Water Diversion/Management Humans need water to live and grow food. Humans have invented several ways for managing water supplies such as building reservoirs and canals for irrigating crops and ensuring a constant supply of water.

Examples The Aral Sea Colorado River The Aral Sea Colorado River

The Aral Sea The Aral Sea is located in Central Asia between Kazakhstan and Uzbekistan. Since the 1960s it has been shrinking due to over irrigation. It is now 20% of its original size. The Soviets used the diverted water to irrigate cotton fields.

The Aral Sea The shrinking of the Aral Sea has caused: A.The collapse of the local fishing industry. B.Increase in respiratory illnesses due to wind stirring up dust of exposed seabed. C.Extinction of plants and animals. The shrinking of the Aral Sea has caused: A.The collapse of the local fishing industry. B.Increase in respiratory illnesses due to wind stirring up dust of exposed seabed. C.Extinction of plants and animals.

The Aral Sea

The Colorado River The Colorado River is an excellent example of how humans can impact the environment through irrigation. The River starts in Colorado and empties into the Gulf of California. On every stretch of the river farmers take water to irrigate crops. People have also built several dams on the river, the most famous is the Hoover Dam.

Changing Landscapes Humans change the landscape of the earth in order to farm or raise animals.

Examples Agricultural Terracing Deforestation Desertification Agricultural Terracing Deforestation Desertification

Agricultural Terracing People practice agricultural terracing in mountainous areas in order to make flat land to farm on.

Think! Look at a map and try to think of some countries or areas where people may practice agricultural terracing. A. The Andes Mountains in South America B. The Himalaya Mountains in Asia

Agricultural Terraces in Peru

Cultivation of Rice in Terraces in China

Deforestation Deforestation is when humans cut down trees faster than they can grow back.

Deforestation A few causes of deforestation are: A.Forest land is cleared for farming or human settlement. B.Forests are cut down and the timber is sold. C.Slash and burn farming in tropical areas. A few causes of deforestation are: A.Forest land is cleared for farming or human settlement. B.Forests are cut down and the timber is sold. C.Slash and burn farming in tropical areas.

Deforestation Much of the world has been deforested including Europe and many parts of the United States. Areas that are becoming rapidly deforested right now are mainly rainforests such as the Amazon Rainforest in Brazil.

Desertification Desertification is an expansion of arid conditions into a non-arid environment. Basically, desertification is when a desert gets bigger due to natural and human causes.

Desertification The fringes of deserts are very fragile environments. If there is a long period of no rain such as a drought this area may turn into a desert. People can also cause desertification by cutting down trees near deserts or herding animals such as cattle, sheep, and goats.

Pollution Humans cause air, water, and soil pollution that harm the environment.

Air Pollution Air pollution is mostly caused by the burning of fossil fuels; oil, coal, and natural gas. Areas with many coal burning power plants, factories, and cars can experience acid rain.

Acid Rain A few areas that have acid rain are the Northeast United States and Canada, the Black Forest region in Germany, and China. Acid rain can kill vegetation and fish in streams and lakes over a period of time.

Water Pollution Water pollution is caused by: A.Runoff that contains pesticides and fertilizers B.Waste from heavy industry that contains metals and chemicals C.Raw sewage D.Oil spills and waste from ships Water pollution is caused by: A.Runoff that contains pesticides and fertilizers B.Waste from heavy industry that contains metals and chemicals C.Raw sewage D.Oil spills and waste from ships