Climate ChangeClimate Change
andand
Greenhouse Effect NotesGreenhouse Effect Notes
What we want to know?What we want to know?
What is climate change?What is climate change?
What is the greenhouse effect?What is the greenhouse effect?
How will climate change affect the earth?How will climate change affect the earth?
How will it affect me?How will it affect me?
What can I do about it?What can I do about it?
Any other questions?Any other questions?
Basics of Manmade Climate ChangeBasics of Manmade Climate Change Earth has existed for 4.5 billion years.Earth has existed for 4.5 billion years. Earth’s climate has changed due to natural cycles Earth’s climate has changed due to natural cycles
in the past.in the past. Many times, these cycles push the Earth to Many times, these cycles push the Earth to
extreme environments and climates.extreme environments and climates. However, human activities have introduced new However, human activities have introduced new
impacts to our environments we can’t ignore.impacts to our environments we can’t ignore. These human activities are increasing greenhouse These human activities are increasing greenhouse
gases that enhance and have an impact on gases that enhance and have an impact on Earth’s climate.Earth’s climate.
If nothing is done, these changes will reach a If nothing is done, these changes will reach a tipping point of no return.tipping point of no return.
What is the Earth’s Atmosphere What is the Earth’s Atmosphere made of?made of?
Where is the atmosphere most Where is the atmosphere most dense?dense?
The atmosphere is most The atmosphere is most densedense at the at the Earth’s surface. Earth’s surface.
The atmosphere gets The atmosphere gets lessless dense the dense the farther you are from the earth’s farther you are from the earth’s surface.surface.
Why doesn’t the atmosphere float Why doesn’t the atmosphere float away?away?
The earth’s gravity holds onto it (just The earth’s gravity holds onto it (just like you!)like you!)
The Earth’s AtmosphereThe Earth’s AtmosphereTroposphereTroposphere
The lowest layer of the atmosphere The lowest layer of the atmosphere (the troposphere) contains (the troposphere) contains 90%90% of the of the atmosphere’s atmosphere’s massmass and is where the and is where the weatherweather occurs. occurs.
The Earth’s AtmosphereThe Earth’s AtmosphereStratosphereStratosphere
Stratosphere contains the ozone layer (0Stratosphere contains the ozone layer (03))
003 absorbs UV radiation absorbs UV radiation
Ozone is Ozone is badbad for us to breathe but for us to breathe but goodgood in in the stratospherethe stratosphere
Solar RadiationSolar Radiation
And why it’s importantAnd why it’s important
What is solar radiation?What is solar radiation?
Solar radiation is Solar radiation is energyenergy from the sun from the sun
What is solar radiation?What is solar radiation?
Energy from the sunEnergy from the sun Electromagnetic waves (type of energy that Electromagnetic waves (type of energy that
can move through space)can move through space) Comes in different Comes in different wavelengthswavelengths Generally, the Generally, the shortershorter the wavelength the the wavelength the
more “intense” (higher energy) the radiationmore “intense” (higher energy) the radiation
Why is solar radiation important?Why is solar radiation important?
Is the basis of nearly all food chainsIs the basis of nearly all food chains Keeps our earth warmKeeps our earth warm Drives all wind and weatherDrives all wind and weather Important to understand climate changeImportant to understand climate change
Wavelength SizesWavelength Sizes
Solar Radiation
The three types of solar radiation are:The three types of solar radiation are:1. Ultra-violet (UV), which is short 1. Ultra-violet (UV), which is short
wavelengths and harmful.wavelengths and harmful. The ozone layer The ozone layer protects us from UV rays. protects us from UV rays.
The three types of solar radiation are:The three types of solar radiation are:
2. Visible light (what humans see). 2. Visible light (what humans see). Wavelengths are longerWavelengths are longer
Three types of solar radiation are:Three types of solar radiation are:
3. Infrared radiation (what we feel as heat). 3. Infrared radiation (what we feel as heat). These are really, really long wavelengths These are really, really long wavelengths and important to understand for greenhouse and important to understand for greenhouse effect. These are what greenhouse gases effect. These are what greenhouse gases ABSORB.ABSORB.
What happens when solar What happens when solar radiation strikes Earth?radiation strikes Earth?
1. 50% of solar radiation is absorbed by the 1. 50% of solar radiation is absorbed by the earth’s surfaceearth’s surface (as heat energy) (as heat energy)
2.2. 20% 20% absorbed by atmosphereabsorbed by atmosphere
3.3. 30% 30% reflected back into outer spacereflected back into outer space
4.4. We’re interested in the heat absorption We’re interested in the heat absorption part of our atmosphere. part of our atmosphere.
Then what happens?Then what happens?
This absorbed This absorbed heat energyheat energy is eventually is eventually transferred back to the atmosphere through transferred back to the atmosphere through infrared radiation. These were the really long infrared radiation. These were the really long wavelengths. wavelengths.
Greenhouse gasesGreenhouse gases, such as , 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 Similar to a car on a hot day….on a hot day….
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!
The car behaves like the Earth
The windshield acts like the atmosphere
What is a Greenhouse?What is a Greenhouse?
A greenhouse is a A greenhouse is a
little house made little house made
of glassof glass
or plastic or plastic
windows. windows.
What is a greenhouse? (cont’d)What is a greenhouse? (cont’d)
Sunlight comes in warming the air inside the Sunlight comes in warming the air inside the greenhouse. Heat can’t escape because of greenhouse. Heat can’t escape because of the windows. A greenhouse is warmer than the windows. A greenhouse is warmer than the air outside. People can grow plants in the air outside. People can grow plants in greenhouses in the winter because it’s warm greenhouses in the winter because it’s warm inside the greenhouse. inside the greenhouse.
The Greenhouse Effect on EarthThe Greenhouse Effect on Earth Earth’s atmosphere acts like a greenhouse. Earth’s atmosphere acts like a greenhouse.
It lets sunlight in and the sunlight warms the It lets sunlight in and the sunlight warms the air. The atmosphere traps the warm air – air. The atmosphere traps the warm air – like a greenhouse!like a greenhouse!
The Greenhouse Effect on the EarthThe Greenhouse Effect on the Earth
What are greenhouse gases?What are greenhouse gases?
These are the gases in the atmosphere These are the gases in the atmosphere that absorb infrared radiation and hold that absorb infrared radiation and hold in the heat and make the greenhouse in the heat and make the greenhouse effect happen.effect happen.
What are the greenhouse gases?What are the greenhouse gases?
These gases are:These gases are:
COCO22 Carbon dioxide
CH4 Methane
N2O Nitrous Oxide
H2O Water
Distribution of Greenhouse Gases in Earth’s Atmosphere
What’s the big deal with Greenhouse What’s the big deal with Greenhouse Effect?Effect?
We We NEEDNEED the greenhouse effect to live!!! the greenhouse effect to live!!!
Without the greenhouse Without the greenhouse
effect, the whole earth would effect, the whole earth would
be be below freezingbelow freezing every night! every night!
The plants would freeze and The plants would freeze and
die. There would be no die. There would be no
oxygen. oxygen.
We would all DIE!We would all DIE!
The Greenhouse EffectThe Greenhouse Effect
The greenhouse effect is similar to a car on a hot The greenhouse effect is similar to a car on a hot day. The day. The most commonmost common greenhouse gas is CO greenhouse gas is CO2
(carbon dioxide). It absorbs infrared heat REALLY well.
Humans increase COCO2 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?What’s your carbon footprint?
Greenhouse EffectGreenhouse Effect
Our animals also contribute Our animals also contribute methanemethane to the atmosphere.to the atmosphere.
Example: Cow farts, Cow poop, and Example: Cow farts, Cow poop, and decomposing thingsdecomposing things
Oops,Pardon
Me!
ClimateClimateChangeChange
The realities and The realities and mythsmyths
Scientists Scientists agreeagree that…that…
Some parts of the earth are Some parts of the earth are warming and other parts warming and other parts coolingcooling..
The warming is caused The warming is caused primarily by primarily by increasingincreasing greenhouse gases.greenhouse gases.
WarmingWarming will continue unless will continue unless greenhouse gas emissions greenhouse gas emissions through human activities are through human activities are reducedreduced..
Scientists Scientists disagreedisagree about…about…
The rate of warmingThe rate of warming The impact of climate The impact of climate change on change on ecosystems, human ecosystems, human health, etc. health, etc.
EvidenceEvidence Direct Direct temperaturetemperature and and greenhouse gas greenhouse gas observations over the observations over the past past 150150 years years
Temperature & COTemperature & CO22 data data from ice core samples from ice core samples over the past over the past 400,000400,000 yearsyears
EvidenceEvidence Glacier DataGlacier Data– glaciers in European Alps glaciers in European Alps
have shrunk 30-40%have shrunk 30-40%– glaciers in New Zealand have glaciers in New Zealand have
shrunk 25%shrunk 25%– glaciers on Mt. Kilimanjaro glaciers on Mt. Kilimanjaro
(Kenya) have shrunk 60%(Kenya) have shrunk 60%– All glaciers PNW are also All glaciers PNW are also
shrinkingshrinking
Of course, this is Of course, this is something that could something that could
NEVER be proved NEVER be proved because….because….
Could never observe it all Could never observe it all directly – always have to directly – always have to rely on some rely on some inferenceinference
Can’t perform a Can’t perform a controlledcontrolled experiment with the earth with the earth
Possible Impacts:Possible Impacts: Melting ice (glaciers, etc.)Melting ice (glaciers, etc.) Decreased snow packs Decreased snow packs
(leading to drought)(leading to drought) Rising sea levels Rising sea levels Coastal floodingCoastal flooding Changes in ocean salinity Changes in ocean salinity (saltiness)
Possible Impacts:Possible Impacts: Changes in ocean currentsChanges in ocean currents Increased Increased temperaturetemperature & heat & heat
waveswaves Decreased Decreased temperaturetemperature and and
dramatic coolingdramatic cooling Changes in Changes in precipitationprecipitation (less in (less in
some areas, more in others)some areas, more in others) More extreme weather events More extreme weather events
(storms, hurricanes, etc.)(storms, hurricanes, etc.)
Possible Impacts:Possible Impacts: Decreased crop/food Decreased crop/food productionproduction
ExtinctionExtinction of many of many species – gone species – gone forever!forever!
