Humans and the Environment

Standard 4.8

What is the fastest growing city?

New York? Los Angeles? Houston?– No, Las Vegas

Will Las Vegas run out of resources?

How long can Las Vegas keep growing?

Resources Renewable

– Wind, solar and hydroelectric power Nonrenewable

– Exist in finite amounts in Earth’s crust– Coal, oil, natural gas

Will we run out?

Resources Saudi Arabia has 24% of the world’s

petroleum reserves Countries must import all of the oil they use Developed countries use more than

undeveloped countries US uses about 24% of Earth’s commercial

energy although we only have 5% of the population

Resources India

– Developing country has 17% of Earth’s population and uses only 2% of the commercial energy

Angola (West Africa)– Country has resources but cannot meet

their needs because of political and economic problems

Angola Have rich deposits of oil, diamonds

and valuable minerals but most people are poor

Most people will not live past 47 because of malnutrition, unsafe drinking water, and lack of adequate health care

Civil war going on for 25 years

Conservation of Resources

Conservation – is the careful use of a resource so that its supply will last longer

How and what can we conserve? Ways to conserve – source reduction, reuse

of products, and recycling, use more energy efficient appliances, purchase cars with better gas mileage, soil conservation, forest conservation

Making a Difference Conservation saves resources and

money– Replace incandescent light bulbs with

fluorescent bulbs Cost more initially but uses 75% less energy

– Use appliances that are more energy efficient

– See house attachment

Location, Location, Location

Why were many cities located on the water when they were founded?– In the 1600s and 1700s boats were the

main form of transportation– Pittsburgh was extremely important

transportation center because of its location on the 3 rivers

The Steel City PA contained numerous coal mines Coal was an important resource in making

steel By the mid-1800s PA started to use coke for

iron and steel making Coke – almost pure carbon substance made

from bituminous coal – the soft coal deposits of western PA

Pittsburgh became a steel center because of the resources needed for steel were nearby

PA Resources By 1900 Pittsburgh steel mills

produced 2/3 of the steel produced in the US

PA major resources – coal, iron and steel

Oil – Drake oil company drilled in Titusville and hit oil in 1859

Air Pollution Two main classes

– Primary – those that factory smokestacks and motor vehicle tailpipes release into the air

Examples: soot, volcanic ash, dust or sea salt– Secondary – new substances that form as

primary pollutants react with each other and with what is already in the atmosphere

Example: Smog Usually come from three forms – Aerosols,

gases and particulates

Air Pollution Aerosols – particles so

tiny that they remain suspended in the air

Gases – compounds that form the basic substance of air

Particulates – particles in the air (large or small

Acid Deposition Rain is naturally slightly acidic In some places rain can be 10x more acidic

than normal Acid deposition – consists of acids or acid-

forming substances that fall from the atmosphere to the ground– Commonly caused by plants and factories that

release sulfur dioxide and nitrogen dioxide into the air which forms sulfuric acid and nitric acid

– Can harm people, ecosystems and animals

Greenhouse Gases Greenhouse gases

– Keeps Earth from being a cold hostile environment

– Include carbon dioxide, methane, water vapor, ozone, nitrogen oxides and chlorofluorocarbons

Greenhouse effect – natural process in which heat is trapped near Earth’s surface by the atmosphere– Example: think of the way heat is trapped in your

car on a hot summer day

Global Warming Increased carbon dioxide into the

atmosphere increases the temperature Global warming – unnatural warming

of the average temperature of the atmosphere near Earth’s surface as a result of the increase in atmospheric greenhouse gases such as CO2

Effect of Global Warming Melting of polar ice caps causing a sea

level rise Low-lying islands could flood and

disappear Warmer climate zones could move

towards the poles Plants and animals must adjust or die Ecosystems would change

Ozone Depletion Ozone – molecule composed of three atoms

of oxygen Forms a protective layer around the planet

that stops 99% of the sun’s harmful ultraviolet radiation from reaching Earth’s surface

CFCs release chlorine into the atmosphere, which is broken down by UV radiation, which then breaks down the ozone into oxygen molecules

Effects of Ozone Depletion

More severe sunburns Greater incidence of cataracts and

skin cancer Harm phytoplankton (alter food chains) Decrease crop yield and damage

forests

Sewage Discharge Sewage moves from drain to treatment plant and

then it is released into surface waters In some places storm water drains and sewage

pipes are the same – during heavy rainfall the two can combine

Release of raw sewage into surface water can cause the growth of bacteria, viruses and other microorganisms that cause disease

This is why public health experts do not allow swimming near storm water outflow pipes after a heavy rainfall

Nutrient Runoff Farm runoff such as

fertilizer can flow into surface water and cause algae blooms

Algae blooms – huge clumps of algae that are eaten by oxygen-using bacteria when they die

Nutrient Runoff Decomposers will suck all of the

oxygen out of an area killing the aquatic life

As a result dead zones are formed Laundry detergent also contributes to

nutrients in sewage because they contain phosphates

Nutrient Overload Can lead to eutrophication

– Where nitrates and phosphates also stimulate the excessive growth of algae and other aquatic plants

– Also leads to a lack of oxygen

Petroleum Spills Oil – contains toxic

substances that kills aquatic life

Oil coating destroys the ability of fur or feathers to insulate animas from cold or help them float, causing animals to freeze or drown

Population Growth Increased demands for natural resources

and increased impacts on the natural environment

Example: Urban area spread into Florida Everglades– Decreased habitat– Increased Pollution– Endangered species – Florida panther and

American crocodile as a result

Overfishing Situation in which commercial fisheries take

more fish than the population can naturally replace

70% of the world’s marine stocks are overfished, depleted or fished to capacity

Populations of Atlantic cod, Atlantic swordfish, sharks and blue fin tuna have decreased

Forests Offer watershed

protection Maintain the

atmosphere’s carbon balance

Sustain biodiversity Also, provide paper,

wood and fuel