Human Impacts on the Environment

People

Population All the members of a species living in a given area Human population has exploded over the last couple centuries due to improved health care, clean water, etc

Carrying Capacity The largest number of individuals of a given species that Earth’s resources can support and maintain for a long period of time populations that exceed carrying capacity will begin to die off due to lack of resources (food, water, space)

Impacts on Land

Humans Using Land - Forest Resources Trees are cut down to make wood and paper products, and to clear land for development Deforestation removal of large area of forests for human purposes

Effects of Deforestation Habitat destruction Soil erosion plant roots hold soil in place; without plants the soil erodes away Air quality less oxygen and more carbon dioxide in the air

Humans Using Land - Agriculture Large areas of land cleared for farming and cattle grazing Effects of Agriculture Fertilizers add excess nitrogen to the soil pollute groundwater Desertification the development of desert-like conditions due to human activities can occur due to soil erosion and/or over farming

Humans Using Land - Mining Removal of rocks and minerals from the ground Effects of Mining disturbing habitats changes the landscape water pollution from runoff

Construction and Development Urbanization the movement of human populations into cities Urban Sprawl the development of land for houses and other buildings near a city Effects of Urbanization habitat destruction reduced water quality due to increased runoff

Positive actions Preservation Governments can protect land by setting aside wild areas There are laws about how the resources there can be removed Forests are complex but they can be managed to preserve the ecosystem Select-cutting- only certain trees in one area are cut down rather than lots of trees or all the trees Reforestation- replanting trees that have been cut or burned down Reclamation- restoring land that has been disturbed by mining

Positive actions Green Spaces Cities use green spaces to create natural environments in urban settings They provide places for recreation for people and habitat for wildlife They reduce runoff and improve air quality as plants take up extra carbon dioxide

Positive actions Reusing, Reducing, & Recycling Composting Reduces the amount of trash that ends up in landfills. It involves mixing food scraps, leaves, and grass clippings and adding the decayed product to soil.

Impacts on Water

Water as a Resource most water is used in power plants to generate electricity

Sources of Water Pollution Point-Source Pollution Nonpoint-Source Pollution pollution from a single source that can be identified ex. oil spills, mining runoff pollution from several widespread sources that cannot be traced to a single location ex. agricultural and urban runoff Most of the United States’ water pollution is nonpoint-source

Positive Actions National Initiatives: How You Can Help: Clean Water Act regulates sources of water pollution Safe Drinking Water Act protects supplies of drinking throughout the country How You Can Help: Reduce use of harmful chemicals Dispose of waste safely Conserve water

Impacts on the Atmosphere

Types of Air Pollution - Smog nitrogen and carbon compounds are released from burning fossil fuels these compounds react with sunlight to make ozone and other chemicals

Types of Air Pollution – Acid Rain rain or snow that has a lower pH than that of normal rainwater makes soil more acidic, making it difficult for plants to survive

Other Types of Air Pollution Particulate Matter mix of both solid and liquid particles in the air ex. smoke, dust CFCs destroy ozone molecules Carbon Monoxide released from cars and forest fires

Global Warming burning fossil fuels releases excess amounts of carbon dioxide into the air this can lead to an increase in Earth’s average surface temperature

Effects of Global Warming Melting of ice caps and a rise in sea level More storms due to higher ocean temperatures Extinction of cold-weather species

The Greenhouse Effect The natural process that occurs when gases in the atmosphere absorb and reradiate thermal energy from the Sun Increased carbon dioxide traps more heat in the atmosphere

Health Disorders Air pollution can cause respiratory problems, including asthma attacks, in which the passageways in the lungs become narrower and breathing becomes difficult. The government measures and reports air quality using the Air Quality Index, which is a scale that ranks the level of ozone and other pollutants.

Positive actions Montreal Protocol Clean Air Act Countries around the world have agreed to phase out CFC’s and to lower emissions of green house gases to help reduce problems due to Air pollution Clean Air Act Since it was passed in 1970, we have seen a 50% reduction in pollutants that cause acid rain and a 90% reduction in air pollution from factories.

Positive actions Using Renewable Energy Using Less Energy Renewable resources such as solar power, wind power, and geothermal energy helps reduce air pollution Using Less Energy Helps reduce pollution and improve the quality of all our important resources: water, air, soil