Human Impact on the Human Impact on the EnvironmentEnvironment::

A look at the ozone layer, global warming, A look at the ozone layer, global warming, acid rain, deforestation, and vehicle acid rain, deforestation, and vehicle emissions…emissions…

The Ozone LayerThe Ozone Layer Ozone occurs Ozone occurs

naturally in the naturally in the layer of our layer of our atmosphere atmosphere called the called the stratosphere.stratosphere.

The ozone layer The ozone layer protects us from protects us from ultraviolet light.ultraviolet light.

Ozone DepletionOzone Depletion

Human made chemicals Human made chemicals called CFCs are called CFCs are

damaging the ozone damaging the ozone layer.layer.

CFCs are found in…CFCs are found in… Refrigerator coolantsRefrigerator coolants Air conditioner coolantsAir conditioner coolants StyrofoamStyrofoam Propellants in spray cansPropellants in spray cans

The ozone layer is decreasing over The ozone layer is decreasing over both the north and south poles.both the north and south poles.

More ultraviolet light means…More ultraviolet light means… Problems with skin cancerProblems with skin cancer

CataractsCataracts Faster aging of skinFaster aging of skin

Greenhouse EffectGreenhouse Effect CO2, Methane and water vapor CO2, Methane and water vapor

NATURALLY create a layer that NATURALLY create a layer that traps heat close to the earth to traps heat close to the earth to maintain Earth’s temperature rangemaintain Earth’s temperature range

This is NORMAL, BUT…. This is NORMAL, BUT….

Global WarmingGlobal Warming The more CO2 and Methane The more CO2 and Methane

there is, the more heat gets there is, the more heat gets trapped!trapped!

BBecause of us, the greenhouse ecause of us, the greenhouse gases in the atmosphere gases in the atmosphere increase over time causing increase over time causing temp to rise.temp to rise.

What’s a degree or two??What’s a degree or two?? To you, nothing. To the polar ice To you, nothing. To the polar ice

caps, a lot!!caps, a lot!! If they melt, they add tons of If they melt, they add tons of

freshwater to the salt water freshwater to the salt water oceans. oceans.

This change in salinity can This change in salinity can change the flow of waterchange the flow of water

What’s a degree or two??What’s a degree or two?? We owe our temperate climate to We owe our temperate climate to

the northern flow of warm waters the northern flow of warm waters of the equatorof the equator

No warm water, no warm No warm water, no warm weather, North America’s climate weather, North America’s climate may be dramatically colder…. may be dramatically colder…. Arctic?Arctic?

Acid RainAcid Rain ph of pure ph of pure

water = 7water = 7 pH of normal pH of normal

rain = 5.4 – 7rain = 5.4 – 7 Mixes with Mixes with

CO2 to form a CO2 to form a mild acidmild acid

pH of acid rain pH of acid rain < 5.4< 5.4

Acid RainAcid Rain When fossil When fossil

fuels are fuels are burned, they burned, they release sulfur release sulfur and nitrogen and nitrogen oxides which oxides which form sulfuric form sulfuric and nitric acid and nitric acid when they mix when they mix with water.with water.

Acid RainAcid Rain The pH of The pH of

lakes, soil, lakes, soil, plant life is plant life is lowered. lowered. Homeostasis Homeostasis may be may be destroyed!destroyed!

A Beautiful Sunset?A Beautiful Sunset?

A colorful A colorful sunset like this sunset like this may be caused may be caused by dust and by dust and pollutants in pollutants in the the atmosphere…atmosphere…

The acid rain changes the pH of The acid rain changes the pH of ecosystems, making the ecosystems, making the

environment too extreme for environment too extreme for plants and animals.plants and animals.

DeforestationDeforestation Forests around the world are Forests around the world are

being cleared at an alarming being cleared at an alarming rate.rate.

Deforestation involves Deforestation involves clearing trees from an area clearing trees from an area

without replacing them.without replacing them.

Today, the problem of Today, the problem of deforestation is especially deforestation is especially

disturbing in the tropical rain disturbing in the tropical rain forests.forests.

Also increases CO2 if trees are cleared by burning!

Don’t even benefit from the wood!

Vehicle EmissionsVehicle Emissions

Automobile Automobile emissions are emissions are responsible for…responsible for…

at least 1/2 of all at least 1/2 of all urban air urban air pollution.pollution.

about 1/4 of all about 1/4 of all carbon dioxide carbon dioxide released into the released into the atmosphere.atmosphere.

Other Sources of Air Other Sources of Air PollutionPollution

IndustrialIndustrialemissionsemissions

Fossil Fuel Fossil Fuel CombustionCombustion

LivestockLivestock

Endangered species and Endangered species and Extinct SpeciesExtinct Species

Why?Why? Development: leads to loss of habitat; Development: leads to loss of habitat;

organisms are force to move somewhere organisms are force to move somewhere where they are not suitably adaptedwhere they are not suitably adapted

Hunting: obvious….Hunting: obvious….

Introduction of new species: We bring in Introduction of new species: We bring in something that doesn’t belong. Maybe it something that doesn’t belong. Maybe it out competes, or preys on other species. out competes, or preys on other species.