KEY CONCEPT As the human population grows, the demand for Earth’s resources increases.

Earth’s Carrying Capacity We refer to the amount of people that Earth can support as the Carrying Capacity of Earth. Thomas Malthus (Late 1700’s) – Claimed that the human population was growing faster than Earth’s resources could support. Malthus’ prediction was off because of the advances in technology. US Population Over Time

Earth’s human population continues to grow. Earth’s human carrying capacity is unknown.

Technology has helped to increase Earth’s carrying capacity. gas-powered farm equipment – Increased world food production. medical advancements – Increase population growth. Antibiotics and antiseptics have lowered infant mortality and the spread of disease.

The growing human population exerts pressure on Earth’s natural resources. Nonrenewable resources are used faster than they form. they cannot be replace in our lifetime. coal oil The growing use of these limited resources will lead to energy crises in the decades ahead unless technologies are developed to use other forms of energy.

Renewable resources cannot be used up or can replenish themselves over time. wind water sunlight Growing use of nonrenewable resources may lead to a crisis. Resources must be properly managed.

Effective management of Earth’s resources will help meet the needs of the future. Earth’s resources must be used responsibly. Careless use of resources makes them unavailable to future generations. Plants for example can be renewable if managed. Easter Island is an example of irresponsible resource use.

Easter Island Inhabitants cut down the trees faster than they could grow back. Without trees, there was no wood for shelter and building boats. Without boats, there was no fishing and therefore no food. As a result, people disappeared for Easter Island.

An ecological footprint is the amount of land needed to support a person. The United States uses more resources and produces more waste than any other country on Earth. The land must produce and maintain enough food and water shelter energy Waste Global Environmental Issues Videos

Ecological Footprint The size of an Ecological Footprint depends on: Amount and efficiency of resource use. Amount and toxicity of waste produced. Ecological Footprint Calculator

Several factors affect the size of the ecological footprint. amount and efficiency of resource use amount and toxicity of waste produced

Ecological Footprint Many developing countries like China and India have small ecological footprints per person, but large populations. Developed and Developing Nations As the world population continues to grow, humans face the challenge of living sustainably and preserving Earth’s resources for our future and future generations. What can we do individually, nationwide, and globally to preserve our future?

KEY CONCEPT Fossil fuel emissions affect the biosphere.

Pollutants accumulate in the air. Pollution is any undesirable factor added to the air, water, or soil. Ex. Microscopic air particles, waste products from factories and sewers, household chemicals, etc. Smog is one type of air pollution. sunlight interacts with pollutants in the air pollutants produced by fossil fuel emissions such as burning gas and oil made of particulates and ground-level ozone

Smog and Ozone Particulates – Microscopic bits of dust, metal, and unburned fuel. 1-10 microns in size. Can stay in the atmosphere for weeks before settling. Can be inhaled and can cause many different types of health problems. Fossil Fuels

Smog and Ozone Ground-level Ozone – Produced when nitrogen dioxides (NO2) from fossil fuel combustion combine with oxygen (O2) to form ozone (O3). Ozone is harmful to organisms at ground level, but plays a critical role in protecting Earth’s biosphere from harmful UV rays from the sun. CFC pollution has caused holes in our ozone layer.

Atmospheric Hazard Great Smog of 1952

Smog can be harmful to human health. Acid rain is caused by fossil fuel emissions. produced when pollutants in the water cycle cause rain pH to drop can lower the pH of a lake or stream can harm trees

Acid Precipitation pH Scale

Precipitation pH values for U.S. in 2003

Damage to Forests by Acid Precipitation

Acid Rain Accelerates Chemical Weathering of Stone Monuments and Structures

Air pollution is changing Earth’s biosphere. The levels of atmospheric carbon dioxide rise and fall over time. High levels of carbon dioxide are typical of Earth’s warmer periods.

sunlight penetrates Earth’s atmosphere The greenhouse effect slows the release of energy from Earth’s atmosphere. sunlight penetrates Earth’s atmosphere energy is absorbed and reradiated as heat greenhouse gases absorb longer wavelengths Greenhouse gas molecules rerelease infrared radiation methane (CH4) water (H2O) carbon dioxide (CO2)

Global warming refers to the trend of increasing global temperatures. False color animation Global Warming Video North Pole

Natural Causes of Global Warming Greenhouse gases. Sunspots that are exploding cause the temperature to rise on earth. Volcanic eruptions naturally release greenhouse gases; also damage plants that filter out CO2. Earth’s orbit has changed, resulting in changes of temperature, depending on distance from the sun. Methane gas is naturally released from Arctic Tundra and Wetlands. Animal flatulence and manure. (methane)

KEY CONCEPT Pollution of Earth’s freshwater supply threatens habitat and health.

Water pollution affects ecosystems. Pollution can put entire freshwater ecosystems at risk.

Water Pollution Affects Ecosystems Runoff from farms and cities contain toxic chemicals and debris that can contaminate freshwater ecosystems. Ex. Detergents and fertilizers pollute lakes and stimulate plant and algae growth. Can result in Eutrophication – Suffocation a lake due to lack of oxygen.

Indicator species provide a sign of an ecosystem’s health. amphibians top predators Also known as a bioindicator

Indicator Species Frogs – Skin is water permeable and direct contact with pollutants can cause deformities such as extra arms and legs, as well as body tumors. Aquatic species show direct effects of pollution. Terrestrial species show environmental impacts differently.

Indicator Species Forster’s Tern – A coastal bird that occupies a niche at the top of the food web. Eats fish. Large amounts of chemical contaminants have been found in the tissues of dead terns. Decrease in populations of Terns could disrupt the balance of the aquatic ecosystem.

Biomagnification causes accumulation of toxins in the food chain. Pollutants can move up the food chain. predators eat contaminated prey pollution accumulates at each stage of the food chain Top consumers, including humans, are most affected.

Biomagnification caused decreasing Bald Eagle populations. Caused by spraying the pesticide DDT. Resulted in eggs being laid with thin shells. Birth rates decreased dramatically DDT was banned in the U.S. and Bald Eagles have been making a comeback nationwide.

Other victims of Biomagnification Beluga whale – Some carcasses have been treated as hazardous waste Humans – Small amounts of PCB’s have been found in the blood of newborn babies. May affect the growth and development of young children.

KEY CONCEPT The impact of a growing human population threatens biodiversity.

Preserving biodiversity is important to the future of the biosphere. The loss of biodiversity has long-term effects. loss of medical and technological advances extinction of species loss of ecosystem stability

Loss of habitat eliminates species. Habitat fragmentation prevents an organism from accessing its entire home range. occurs when a barrier forms within the habitat often caused by human development

Habitat corridors are a solution to the problem. corridors can be road overpasses or underpasses allow species to move between different areas of habitat

Introduced species can disrupt stable relationships in an ecosystem. An introduced species is one that is brought to an ecosystem by humans. accidental purposeful Invasive species can have an environmental and economic impact.

Invasive species often push out native species. Burmese python (Florida Everglades)

Invasive species often push out native species. mice (Australia)

Invasive species often push out native species. kudzu (southeastern United States)

KEY CONCEPT Conservation methods can help protect and restore ecosystems.

Sustainable development manages resources for present and future generations. Sustainable development meets needs without hurting future generations. resources meet current needs resources will still be available for future use

The timber industry has started to adopt sustainable practices. Global fisheries have adopted several sustainable practices. rotation of catches fishing gear review harvest reduction fishing bans

Conservation practices focus on a few species but benefit entire ecosystems. The Endangered Species Act works to protect individual species from extinction. A listed species is often called an umbrella species. the habitat in which the species lives must be protected other species are protected because they share the ecosystem

Protecting Earth’s resources helps protect our future. The Environmental Protection Agency (EPA) was created in 1970. The EPA develops policies and regulations to protect the environment. Legislation helps to protect the environment and endangered species. Clean Air Act Clean Water Act Endangered Species Act

The National Park Service helps manage public lands. The park system includes over 390 areas, covering 84 million acres.

There are several ways that people can help protect the environment. control population growth develop sustainable technology and practices protect and maintain ecosystems