Human Impact on the Human Impact on the EnvironmentEnvironment::

A look at the ozone layer, climate change, A look at the ozone layer, climate change, acid rain, deforestation, and vehicle acid rain, deforestation, and vehicle emissions…emissions…

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 maintainmaintain

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?

Invasive SpeciesInvasive Species

Organisms not native to our Organisms not native to our ecosystemsecosystems1. Out compete native organisms for food1. Out compete native organisms for food

No natural predatorsNo natural predators

2.2. Population of invasive species increasesPopulation of invasive species increases2.2. Population of native species decreasesPopulation of native species decreases

3.3. Invasive species spreadsInvasive species spreads2.2. Native species and prey species may die out Native species and prey species may die out

Knotweed outcompeting local plants

Emerald Ash Borer killing Ash Trees

Zebra Mussels eat algae

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 emissions are Automobile emissions are responsible for…responsible for…

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

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

Key contributor Key contributor to ground ozoneto ground ozone

Other Sources of Air Other Sources of Air PollutionPollution

IndustrialIndustrialemissionsemissions

Fossil Fuel Fossil Fuel CombustionCombustion

LivestockLivestock

Erosion and DepositionErosion and Deposition Breaking down and building up of Breaking down and building up of

landland Happens naturally but SLOWLYHappens naturally but SLOWLY Rate increases when humans: Rate increases when humans:

Knock down trees for developmentKnock down trees for development Redirect water flow Redirect water flow Strip miningStrip mining

Erosion and depositionErosion and deposition

AGAIN IT IS ALL ABOUT AGAIN IT IS ALL ABOUT BALANCE!!BALANCE!!

Our actions throw off nature’s Our actions throw off nature’s balance!balance!

Ecosystem disruptionEcosystem disruption

An An endangered speciesendangered species is a is a population of organisms which is at population of organisms which is at risk of becoming extinct through all risk of becoming extinct through all or a portion of its range or a portion of its range few in numbers, or few in numbers, or threatened by changing environmental threatened by changing environmental

or predation parameters (including or predation parameters (including humans)humans)

Ecosystem disruptionEcosystem disruption

A “A “threatened” species threatened” species is one that is one that is likely to become endangered in the is likely to become endangered in the foreseeable future and that the foreseeable future and that the population is declining.population is declining.

Threatened and Endangered Threatened and Endangered SpeciesSpecies

So what??? Why do we care? So what??? Why do we care?

Human impact on extinctionHuman impact on extinction Harvard biologist E.O. Wilson (1993) Harvard biologist E.O. Wilson (1993)

estimated that Earth is currently losing estimated that Earth is currently losing something on the order of 30,000 species something on the order of 30,000 species per year — which breaks down to the even per year — which breaks down to the even more daunting statistic of some three more daunting statistic of some three species per hour. Some biologists have species per hour. Some biologists have begun to feel that this biodiversity crisis — begun to feel that this biodiversity crisis — this “Sixth Extinction” — is even more this “Sixth Extinction” — is even more severe, and more imminent, than Wilson severe, and more imminent, than Wilson had supposed. had supposed.