How do humans impact their environment?

1. How do humans impact their environment? November 2018

2. Water Diversion/Management • Humans have invented several techniques for managing water supplies such as building reservoirs and canals for irrigating crops and ensuring a constant supply of water.

3. Examples include: • The Aral Sea • Colorado River • Aswan High Dam

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

5. The Aral Sea

7. The Aral Sea

8. The Colorado River • The Colorado 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.

11. Aswan High Dam (Benefits) • The Aswan High Dam was built on the Nile River in 1960 – 1970 • The dam provides around 15% of Egypt’s electricity. • The dam has stopped the Nile River from flooding every year. • The dam created Lake Nasser, which provides water for irrigation and local use.

12. Aswan High Dam (Negatives) • Around 90,000 people had to move. • The dam blocks nutrient rich silt from being deposited on farmland and farmers have to use artificial fertilizers. • Poor irrigation practices have led to an increase of salt in surrounding farmland. • Fish stocks in the Mediterranean have depleted because the dam blocks nutrients from entering the sea.

16. Changes to physical landscapes • Agricultural Terracing • Polders • Deforestation • Desertification

17. Agricultural Terracing • People practice agricultural terracing in mountainous areas in order to make flat land to farm • What are the advantages and disadvantages?

18. Agricultural Terraces in Peru

19. Cultivation of Rice in Terraces in China

20. Polders • A polder is an area of reclaimed land from the sea. • Polders are found in countries with low elevations next to the sea such as Belgium and the Netherlands • What is the risk with reclaiming land from the sea?

21. Netherlands without polders Netherlands with polders

22. Deforestation • Deforestation is when humans cut down trees faster than they can grow back. • A few causes of deforestation are: • Forest land is cleared for farming or human settlement. • Forests are cut down and the timber is sold. • Slash and burn farming in tropical areas.

23. Desertification • Desertification is an expansion of arid conditions into a non-arid environment. • Desertification occurs near deserts. • The region directly south of the Sahara Desert in Africa is called the Sahel. • This area has suffered from rapid desertification due to over grazing, droughts, and poor water management practices.

25. Map of Western Africa showing Sahel

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

27. 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.

28. 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.

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

32. Water Pollution • A few areas that have severe water pollution are: • Most of the rivers in Europe • The Ganges River in India • What are some actions we can take to combat water pollution in these areas?

34. Nuclear Pollution • An example of nuclear pollution is when the Chernobyl nuclear power plant in the former Soviet Union exploded causing radioactive waste to contaminate the air and soil

35. Chernobyl • In 1986, one of the reactors at the nuclear power plant exploded causing a cloud of radioactive material that drifted and fell over parts of Russia and Europe. • Over 300,000 people were forced to evacuate the nearby city of Pripyat and today the city is abandoned.

37. Practice #1 • In your notebook, describe environmental sustainability in your own words, draw a picture of what it looks like and explain, in one paragraph, why it matters to you.