Transcript Global Warming

Global Warming
Ch. 13 Section 3
Greenhouse Effect
• Sunlight enters Earth’s atmosphere
• Earth’s surface radiates heat back to the
atmosphere
– Some heat escapes
– Some heat is trapped by Greenhouse Gases
• Ex: water vapor, carbon dioxide, methane, nitrous oxide
• Trapped heat radiated back to Earth’s surface,
warming the air.
• Without this Earth would be too cold to live on
• However, too many greenhouse gases can trap
too much heat.
Greenhouse Effect
Greenhouse Effect
Greenhouse Gases
- gases that absorb and radiate heat
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Water vapor
Carbon Dioxide
CFC’s
Methane
Nitrous oxide
• Water vapor and CO2 absorb the most heat in
the atmosphere
CO2
• Most is absorbed by the ocean or used by
plants during Photosynthesis
• Therefore, CO2 levels fluctuate with the season
– Summer = less CO2 ---------------------------------------------– Winter = more CO2 ------------------------------------------------
• WHY???
CO2 Levels
There has been a significant rise in CO2 in
the atmosphere in the last 50 years due to
burning fossil fuels
Ice Core Samples
• Can determine the levels of CO2 in the
atmosphere thousands of years ago
CO2 and Temperature
• Because CO2 holds more heat than other gases
in the atmosphere, scientists think that more
CO2 means greater global temperatures
• Therefore…
• Burning = more CO2 = Higher temps.
Temp. and CO2 Levels
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Consequences of Global Warming
• Birds nesting earlier
• Flowering earlier – more allergies
• Change weather patters
– Droughts and flooding
– More hurricanes and typhoons
• Rising sea level
– Flooding of coastal areas
– Erosion of beaches
– Increase in salinity in aquifers
• More mosquitoes that carry diseases
Consequences of Global Warming
• Agriculture
– Most severely effected
– Decreased crop yield
– Could need more irrigation
• Animals
– Shift their geographical range
– Reduce the number of zooplankton
IPCC
• International Panel on Climate Change
– Average global temp. increased by 0.6oC last century
– Snow cover and ice have decreased
– Global sea level has risen
Kyoto Protocol
• 1997, 160 countries
• Requires countries to reduce CO2 and other
greenhouse gas emissions by 5% by 2012
• We did sign, then Bush unsigned us 
Ch. 13
Section 1 Objectives
• Explain the difference between weather and
climate.
• Identify four factors that determine climate.
• Explain why different parts of the Earth have
different climates.
• Explain what causes the seasons
Weather vs. Climate
• Weather – what is happening right at that
moment
– It is cloudy and raining outside
• Climate – the average weather over a long
period of time
– We live in a hot, dry area
Latitude
- distance north or south from the equator
• Determines what type of climate an area has
• The further from the equator the ________
the temperature.
Latitude
• Daylight hours depend on your latitude
– Equator = 12 day and 12 night
– Close to the poles = all day or all night part of the year
Atmospheric Circulation
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Warm air rises
Cold air sinks
Warm air hold more water vapor
When it cools the water vapor condenses into
precipitation
El Nino
• When warm and cold water masses change
location in the Pacific Ocean for a short time
• Causes increased rainfall in the southern US, but
causes droughts in Indonesia and Australia
• La Nina – exact opposite
• Pacific Decadal Oscillation – a long term El Nino
Topography influences on climate
• Topography is the shape of the earth’s surface
• As elevation increases temperature drops
Solar Maximum and Volcanoes
• Solar Maximum – sun emits more ultraviolet
radiation, warming the earth
• Vocanoes – dust and such can block out some
of the sun cooling the earth
Seasonal Climate Change
• Seasons change due to the tilting of earth as it
goes around the sun.
Section 2 Objectives
• Explain why Earth’s atmosphere is like the
glass in a greenhouse.
• Explain why carbon dioxide in the atmosphere
appears to be increasing.
• Explain why many scientists think that the
Earth’s climate may be becoming increasingly
warmer.
• Describe what a warmer Earth might be like.
Ozone layer
- are where ozone (three oxygen atoms) is concentrated in the
stratosphere
• Act like sunscreen for the earth
• Block out UV rays that harm genetic material
Chlorofluorocarbons (CFC’s)
• The miracle chemical
• 1970’s they were used for
– Coolants
– Deodarants
– Hairspray, etc.
• However, at high elevations CFC’s break apart and
the parts destroy and combine with ozone
molecules
• 1 CFC molecule can destroy 100,000 ozone
molecules
The Hole
• First reported in 1985 over the South pole
– Ozone had shrunk by 50 – 98%
– Why over south pole?
How it effects humans
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Worse sunburns
More eye cataracts
Immune system repression (UV-B)
More skin cancer
Montreal Protocol - 1987
• Representative of 36 Nations
• Reduce CFC emissions (only) by 35% between
1989 – 2000
• Now signed by 177 countries
• Global Cooperation Does Work!!!
Differences between Global Warming
and Ozone depletion
• Different type of radiation:
–Infrared vs. Ultraviolet
• Different effect:
–earth warming vs. health problems
• Ozone depletion does not cause
global warming directly
• But, it can effect oceans uptake
of CO2
Do not confuse them
Skin Cancer
Let’s take a skin cancer
quiz!!!
Skin cancer comes in many shapes and
sizes
• Things to watch for
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Shiny or waxy lump
Firm red lumps
Lump that bleeds and does not heal
Itchy red spot that might be tender (not
eczema)
Overt eyes if squeamish
Squamous cell
• upper skin layer, caused by sunlight and tanning
beds, usually curable if treated early, but it can
metastasize
Basal cell
• deeper layer of skin, most common form,
usually caused by sun and tanning lamps,
Malignant melanoma
Worst kind!
• ABCDE rule
– A = asymmetry
– B = borders
– C = color
– D = diameter, over 5mm
– E = elevation
Risk factors
• Skin type
• Sun/tanning exposure
• Freckles
• Family History
How to prevent it
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Sunscreen
Wear hats
Take vitamins (folic acid)
Eat vegetables
Drink Green Tea
Eat Fish
Eat whole grains