Human Impact on the Environment

Trade off Humans have both positive and negative impacts on the environment. Main reason for the negative impact is the human population is increasing. This places increasing demands on natural resources such as food, water, energy and space.

There is no easy solution and every solution has both + and – consequences. Trade off: when a solution has both negative and positive consequences. A consequence is something that naturally follows from an action Consequences can be both positive and negative.

Finite Resources. Finite resources: resources that will eventually run out. Interrelationships The Earth has limited resources to support life. The increasing human population is depleting those resources. Ex. Pollution decreases the amount of oxygen in the air.  

Renewable vs. nonrenewable Renewable resources are resources that are being replaces faster than we can use it up. Example: wood, solar radiation Non-renewable resources: something being used faster than it can be replaced Example: oil, coal, natural gas

Some Detrimental (harmful) Human Activities    Human activities can alter the balance of an ecosystem.    This destruction of habitat, is threatening the stability of the planet's ecosystems.    the damage to the ecosystems may be permanent.  

1. Population growth: Too many people using limited resources Ways Humans Adversely Influence Ecosystems 1. Population growth: Too many people using limited resources 2. Over consumption: Industrialized societies are using more resources per person from our planet than people from poor nations. 3. Advancing Technologies: we introduce technology without knowing how it will influence the environment

4. Direct Harvesting: a large loss of rainforest and its biodiversity. 5. Pollution: pollution has had many adverse influences on air, water and land. 6. Atmospheric Changes: Greenhouse gases due to the burning of fossil fuels and depletion of our ozone layer.

7. Endangered species: species are threatened to extinction due to habitat destruction. 

Invasive Species Importing foreign organisms have caused problems for native organisms (one’s already living there).   They are know as an invasive species AKA exotic species.  This is a species not native to an area, it was imported. They are bad because they can out compete the native animals causing them to go extinct. Some times they have better tools for that environment.

Sometimes they lack predators and their populations increase to high levels. Then they eat all the food and native species go extinct. They tend to disrupts the natural food web that has been there for many years.

Three major environmental problems include: Global Warming Acid precipitation (rain) Ozone depletion

I. Acid Precipitation Most acid rain in New York State is caused by sulfur dioxide and nitrogen dioxide pollution from the burning of fossil fuels such as coal and oil.   They combine with water vapor in the atmosphere and fall back to the earth over New York as acid precipitation.

Some Problems Associated With Acid Precipitation Streams and lakes becoming more acidic, killing fish, frogs and other life. Damage forests and plants and deteriorates buildings

What can be done? We can burn low sulfur coal We can use alternative energy sources such as solar panels for electricity and hot water heaters. We can heat our house with geothermal wells. Geothermal well: well drilled deep into the earth to release heat naturally created.

Geothermal well

Acid precipitation

II. Global Warming Burning fossil fuels and other pollution increases the amount of CO2 in the air Fossil fuels include gasoline, coal and oil. This can potentially increase the earth’s temperature.

Carbon Dioxide is also known as a Greenhouse gas    the increase in level of carbon dioxide and other gases is not allowing infrared or solar heat radiation to escape the planet back into outer space.   This is causing our planet to slowly warm.  

Consequences of Global Warming Rising sea levels and coastal flooding Changed rain patterns resulting in droughts and crop failures Increase in insect diseases in regions Ex. New York State: warmer winters fail to kill the disease carrying insects like West Nile

What can be done? Decrease use of fossil fuels, including electricity. Use alternative forms of energy such as solar panels Car pool to work, take public transit.

III. Ozone Depletion Ozone is another form of oxygen. You breath O2. Ozone is O3. you do not breath this. Ozone decreases the amount of solar radiation that reaches the earth from the sun, also known as UV.

Hole in the ozone layer

What causes Ozone depletion Use of CFC’s or chlorofluorocarbons lowers ozone by breaking up O3 CFC’s are used in some aerosol cans (not as much any more) They are also released from some refrigerators and air conditioning systems. Consequences: skin cancer, cataracts.

Actions being taken by humans to reduce or repair damage to the environment include: 1.  Recycling wastes 2.  Conserving available resources 3. Using cleaner resources (ex: solar over fossil fuels) 4.protection of habitats and endangered species 5. use of biological controls instead of pesticides and herbicides

6. Farming native plants (ex: cocoa in the rainforest) 7. Planting trees to replace those cut down. 8. Rotating crops or planting cover crops to reduce soil loss.  9. passing laws to control pollution, land management, hunting and fishing

What part of the food chain do you think is most affect by toxins? Producer Primary consumer Secondary consumer Tertiary consumer Why?

Biomagnification Biomagnification: the increased concentration of a poison that moves up the food chain. It can start at the plant level. Many little fish eat the plants and get the toxins. Then a large mouth bass eats hundreds of little fish and gets more toxins.

A human fisherman catches several bass with already higher level toxins He eats them all and gets even more. He may accumulate so much toxin that is causes cancer or some other disorder This happens in the Hudson River. Central Hudson has dumped tons of toxins including PCP’s in the river.

Much of the toxins settle in the bottom soil or sediment. Politicians try to correct this by dredging the river or scoop out the bottom sediment. It stirs the toxins back into the water causing more problems.

Human action often has negative consequences for the ecosystem and humans too.  Here are some and they ways the affect our ecosystem.

For each of the following ecological problems, identify the specific cause, their negative effects on the environment, and a way that people are trying to fix the problem: 1. acid rain Cause: Negative effects: How we are trying to fix: 2. deforestation

3. Loss of diversity: Cause: Negative effects: How we are trying to fix: 4.Global warming

5.Introduced (invasive) species Cause: Negative effects: How we are trying to fix: 6. Industrialization:

7. Nuclear Power Cause: Negative effects: How we are trying to fix: 8. use of chemical fertilizers

9. burning fossil fuels Cause: Negative effects: How we are trying to fix: