Download Climate Change

Climate Change
and
Greenhouse Effect Notes
What we want to know?
What is climate change?
What is the greenhouse effect?
How will climate change affect the earth?
How will it affect me?
What can I do about it?
Any other questions?
Basics of Manmade Climate Change
 Earth has existed for 4.5 billion years.
 Earth’s climate has changed due to natural cycles
in the past.
 Many times, these cycles push the Earth to
extreme environments and climates.
 However, human activities have introduced new
impacts to our environments we can’t ignore.
 These human activities are increasing greenhouse
gases that enhance and have an impact on Earth’s
climate.
 If nothing is done, these changes will reach a
tipping point of no return.
What is the Earth’s Atmosphere
made of?
Where is the atmosphere most
dense?
 The atmosphere is most dense at the
Earth’s surface.
 The atmosphere gets less dense the
farther you are from the earth’s
surface.
Why doesn’t the atmosphere float
away?
 The earth’s gravity holds onto it (just
like you!)
The Earth’s Atmosphere
Troposphere
 The lowest layer of the atmosphere
(the troposphere) contains 90% of the
atmosphere’s mass and is where the
weather occurs.
The Earth’s Atmosphere
Stratosphere
 Stratosphere contains the ozone layer (03)
 03 absorbs UV radiation
 Ozone is bad for us to breathe but good in
the stratosphere
Solar Radiation
And why it’s important
What is solar radiation?
Solar radiation is energy from the sun
What is solar radiation?
 Energy from the sun
 Electromagnetic waves (type of energy that
can move through space)
 Comes in different wavelengths
 Generally, the shorter the wavelength the
more “intense” (higher energy) the radiation
Why is solar radiation important?
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Is the basis of nearly all food chains
Keeps our earth warm
Drives all wind and weather
Important to understand climate change
Wavelength Sizes
Solar Radiation
The three types of solar radiation are:
1. Ultra-violet (UV), which is short
wavelengths and harmful. The ozone layer
protects us from UV rays.
The three types of solar radiation are:
2. Visible light (what humans see).
Wavelengths are longer
Three types of solar radiation are:
3. Infrared radiation (what we feel as heat).
These are really, really long wavelengths
and important to understand for greenhouse
effect. These are what greenhouse gases
ABSORB.
What happens when solar
radiation strikes Earth?
1. 50% of solar radiation is absorbed by the
earth’s surface (as heat energy)
2. 20% absorbed by atmosphere
3. 30% reflected back into outer space
4. We’re interested in the heat absorption
part of our atmosphere.
Then what happens?
This absorbed heat energy is eventually
transferred back to the atmosphere through
infrared radiation. These were the really long
wavelengths.
Greenhouse gases, such as CO2,CH4 ,N2O,
H2O and O3 are good absorbers of infrared
radiation – that’s why these are considered
“greenhouse gases!” When they absorb infrared
radiation, the atmosphere becomes warmer – this
is the greenhouse effect!
Similar to a car
on a hot day….
The car behaves like
the Earth
The windshield acts
like the atmosphere
Light energy easily passes through the
windshield, but the longer wavelength
infrared radiation that is re-transmitted by
the car’s interior can’t escape through the
glass very well – thus the car heats up!
What is a Greenhouse?
A greenhouse is a
little house made
of glass
or plastic
windows.
What is a greenhouse? (cont’d)
Sunlight comes in warming the air inside the
greenhouse. Heat can’t escape because of
the windows. A greenhouse is warmer than
the air outside. People can grow plants in
greenhouses in the winter because it’s warm
inside the greenhouse.
The Greenhouse Effect on Earth
Earth’s atmosphere acts like a greenhouse.
It lets sunlight in and the sunlight warms the
air. The atmosphere traps the warm air –
like a greenhouse!
The Greenhouse Effect on the Earth
What are greenhouse gases?
These are the gases in the atmosphere
that absorb infrared radiation and hold
in the heat and make the greenhouse
effect happen.
What are the greenhouse gases?
These gases are:
CO2
Carbon dioxide
CH4
Methane
N 2O
Nitrous Oxide
H 2O
Water
Distribution of Greenhouse Gases in
Earth’s Atmosphere
What’s the big deal with Greenhouse
Effect?
We NEED the greenhouse effect to live!!!
Without the greenhouse
effect, the whole earth would
be below freezing every night!
The plants would freeze and
die. There would be no
oxygen.
We would all DIE!
The Greenhouse Effect
The greenhouse effect is similar to a car on a hot
day. The most common greenhouse gas is CO2
(carbon dioxide). It absorbs infrared heat REALLY
well.
Humans increase CO2 in the atmosphere by
burning fossil fuels (such as gasoline, natural gas,
and coal) and by burning forests is increasing
greenhouse effect to create climate change (not
good).
What’s your carbon footprint?
Greenhouse Effect
Our animals also contribute methane
to the atmosphere.
Example: Cow farts, Cow poop, and
decomposing things
Oops,
Pardon
Me!
Climate
Change
The realities and myths
Scientists agree that…
 Some parts of the earth are
warming and other parts cooling.
 The warming is caused primarily by
increasing greenhouse gases.
 Warming will continue unless
greenhouse gas emissions through
human activities are reduced.
Scientists disagree
about…
 The rate of warming
 The impact of climate
change on ecosystems,
human health, etc.
Evidence
 Direct temperature and
greenhouse gas
observations over the past
150 years
 Temperature & CO2 data
from ice core samples over
the past 400,000 years
Evidence
 Glacier Data
– glaciers in European Alps have
shrunk 30-40%
– glaciers in New Zealand have shrunk
25%
– glaciers on Mt. Kilimanjaro (Kenya)
have shrunk 60%
– All glaciers PNW are also shrinking
Of course, this is something
that could NEVER be
proved because….
 Could never observe it all
directly – always have to rely on
some inference
 Can’t perform a controlled
experiment with the earth
Possible Impacts:
 Melting ice (glaciers, etc.)
 Decreased snow packs (leading to
drought)
 Rising sea levels
 Coastal flooding
 Changes in ocean salinity
(saltiness)
Possible Impacts:
 Changes in ocean currents
 Increased temperature & heat waves
 Decreased temperature and dramatic
cooling
 Changes in precipitation (less in some
areas, more in others)
 More extreme weather events (storms,
hurricanes, etc.)
Possible Impacts:
 Decreased crop/food
production
 Extinction of many
species – gone forever!