Our Impact on the Land

Populations Populations All the individuals of one species living in the same area Population Explosion: Earth’s population is increasing rapidly Medicine, clean water, and better nutrition, have lowered the death rate Number of births has increased because more people are living to child bearing age

Population By 2100, Estimated population of Earth is 11 Billion Almost Twice what it is now

Population Pyramids

How Many People Can the Earth Hold? Earths Carrying Capacity Largest Number of individuals of particular species the environment will support Limited By Space Resources

How do we affect the Environment? Electrical Use Burning Fossils fuels emits pollutants Environment changes when fossil fuels are mined Eating Food It takes land to grow food Use of chemical substances to grow food, can get into water supplies and threaten other species

Strip Mining

Affect the Environment Plastics Made from oil Refining oil produces pollutants Paper Trees are cut down Water and air pollutants are given off in the papermaking process Garbage Needs to be disposed somewhere

Paper Mill

Land Fills

Using Land Farming Feeds People, farmer’s try to grow more and better crops Negative Affects of Farming Chemical Fertilizers Herbicides and pesticides

Using Land Positive affects of Farming Organic Farming: natural fertilizers, crop rotation, biological pest controls No Till Farming: Planting seeds between previous year’s stubble to save top soil Contour Plowing: Rows are tilled across hills and valleys to capture water and soil

Organic Farming

No Till Farming

Contour Planting

Using Land Growing food for Livestock Some believe it would be more efficient to use all the land to grow crops for people Others believe using the land for cattle is important because people need meat and dairy products

Livestock

Using Land Source of Wood Trees are cut down and used for lumber, fuel, and paper Species become extinct each year due to the loss of forests, especially rain forest Less vegetation may cause higher levels of carbon dioxide in the atmosphere Local regions may receive less rainfall

Clear Cut

Selective Cutting

Using Land Developments Buildings, Highways, office buildings, stores and parking lots Paving prevents water from soaking into the soil Instead it runs off into streams and sewers Stream Discharge: volume of water flowing past a point per unit of time

Using Land Pavement In paved areas, heavy rainwater an lead to increased stream discharge, causing flooding Paving prevents rainwater from refilling underground water supplies

Landfills Sanitary Landfills Areas where daily garbage is deposited and covered with soil Lined with plastic, concrete, or clay rich soil to prevent pollutants from leaking into soil or groundwater Many materials do not decompose in landfills As landfills fill up, new ones must be built

Sanitary Landfill

Wastes Hazardous Wastes Wastes that are poisonous that cause cancer, or that can catch fire In many states, they cannot be deposited in sanitary landfills Some can be recycled Phytoremediation: using plants to clean up the soil be removing metal from it

Phytoremediation

Hazardous Waste Landfill

Wastes Cont’d Enzymes Natural Preserves From plant roots increase the rate that organic pollutants break down Natural Preserves Land that is set aside to protect it from environmental problems caused by people

Conserving Resources Conservation Ways to Conserve The careful use of resources to reduce damage to the environment Ways to Conserve Reduce: Use less materials Reusing: Finding another use for an item rather then throwing it away

Ways to Conserve Reusing Recycling Composting: piling yard wastes where they can decompose gradually If everyone in the country used composting, 20% less trash would be put in landfills Recycling Using materials again by converting used materials into new and useful products These processes can save landfill space, reduce energy use and minimize the need to extract raw materials from Earth

Recycling

Composting