Transcript Human Impact on the Environment:

Human Impact on the
Environment:
A look at the ozone layer, climate change, acid
rain, deforestation, and vehicle emissions…
Greenhouse Effect
 CO2,
Methane and water vapor
NATURALLY create a layer that traps
heat close to the earth to maintain
Global Warming
 The
more CO2 and Methane there
is, the more heat gets trapped!
Because of us, the greenhouse
gases in the atmosphere increase
over time causing temp to rise.
What’s a degree or two??
 To
you, nothing. To the polar ice
caps, a lot!!
 If they melt, they add tons of
freshwater to the salt water oceans.
 This change in salinity can change the
flow of water
What’s a degree or two??
 We
owe our temperate climate to the
northern flow of warm waters of the
equator
 No warm water, no warm weather,
North America’s climate may be
dramatically colder…. Arctic?
Invasive Species

Organisms not native to our ecosystems
1. Out compete native organisms for food

2.
Population of invasive species increases
2.
3.
No natural predators
Population of native species decreases
Invasive species spreads
2.
Native species and prey species may die out
Knotweed outcompeting local plants
Emerald Ash Borer killing Ash Trees
Zebra Mussels eat algae
 ph
Acid Rain
of pure
water = 7
 pH of normal
rain = 5.4 – 7
 Mixes
with CO2
to form a mild
acid
 pH
of acid rain
< 5.4
 When
Acid Rain
fossil
fuels are
burned, they
release sulfur
and nitrogen
oxides which
form sulfuric
and nitric acid
when they mix
with water.
Acid Rain
 The
pH of lakes,
soil, plant life is
lowered.
Homeostasis
may be
destroyed!
A Beautiful Sunset?
A
colorful
sunset like this
may be caused
by dust and
pollutants in the
atmosphere…
The acid rain changes the pH of
ecosystems, making the environment
too extreme for plants and animals.
Deforestation
 Forests
around the world are being
cleared at an alarming rate.
Deforestation involves
clearing trees from an area
without replacing them.
Today, the problem of deforestation
is especially disturbing in the tropical
rain forests.
Also increases
CO2 if trees are
cleared by
burning!
Don’t even
benefit from the
wood!
Vehicle Emissions
Automobile emissions are
responsible for…
 at least 1/2 of all urban air
pollution.
 about 1/4 of all carbon
dioxide released into the
atmosphere.
 Key
contributor to
ground ozone
Other Sources of Air Pollution
 Industrial
emissions
 Fossil
Fuel
Combustion
 Livestock
Erosion and Deposition
 Breaking
down and building up of
land
 Happens naturally but SLOWLY
 Rate increases when humans:
 Knock
down trees for development
 Redirect water flow
 Strip mining
Erosion and deposition
 AGAIN
 Our
IT IS ALL ABOUT
BALANCE!!
actions throw off nature’s
balance!
Ecosystem disruption

An endangered species is a population
of organisms which is at risk of becoming
extinct through all or a portion of its range


few in numbers, or
threatened by changing environmental or
predation parameters (including humans)
Ecosystem disruption

A “threatened” species is one that is
likely to become endangered in the
foreseeable future and that the population
is declining.
Threatened and Endangered Species
 So
what??? Why do we care?
Human impact on extinction

Harvard biologist E.O. Wilson (1993)
estimated that Earth is currently losing
something on the order of 30,000 species
per year — which breaks down to the
even more daunting statistic of some
three species per hour. Some biologists
have begun to feel that this biodiversity
crisis — this “Sixth Extinction” — is even
more severe, and more imminent, than
Wilson had supposed.