Is Global Climate Change Happening?
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Weather vs Climate
• Weather: atmospheric conditions in any
given place over a short term.
(i.e. Today will be dry and 95 degrees F)
• Climate: average weather conditions in a
region over a long period of time.
(i.e. Dry season in the southwest)
Global Warming or Climate Change?
• Global Warming – Increase in the
Earth’s average temperature
(i.e. an increase of 1 degree F)
• Global Climate Change – Change in
average weather conditions in a region
over a long period of time
(i.e. increase or decrease; temperature,
precipitation, humidity, storms)
The Climate System
System – A set of parts that interact or
work with each other
The climate system is affected by:
NOAA Slides by Forecast Systems Laboratory.
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Hydrosphere – all of Earth’s water
(solid, gas & liquid). Oceans store and
release Carbon Dioxide or CO2
Hydrosphere Distribution
Cryosphere - all solid water; sea ice, glaciers –
Albedo or reflect Sun’s energy
http://www.google.com/imgres?imgurl=http://www.the-m-factory.com
Biosphere: all life; trees & plants – use,
store and release CO2 (carbon dioxide)
http://www.google.com/imgres?imgurl=http://www.isavo.com
Atmosphere – gaseous layer surrounding
Earth – clouds exert a cooling effect that
slows the evaporation of water
http://www.google.com/imgres?imgurl=http://www.pacificislandtravel.com
Anthrosphere – what humans build; we
burn fossil fuels which releases CO2
The Greenhouse Effect
• The sun’s energy enters the atmosphere
and warms the Earth. Our planet’s
atmosphere traps the heat energy.
• Some of the sun’s energy is reflected
back into space but the remainder is
absorbed by greenhouse gases in the
atmosphere where they help to warm
the planet.
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Without this natural phenomenon our
planet would be 60 degrees F colder
Living things need a temperature of
32-212°F (0-100°C) to survive
.
Greenhouse Gases: Carbon Dioxide
http://www.google.com/imgres?imgurl=http://www.geos.ed.ac.uk
Sources of carbon dioxide emissions are:
Land plants use CO2 from the atmosphere and
return it when they die
Aquatic plants use CO2 from the water and
return it when they die
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Animal and plant respiration emits CO2
into the environment
Burning of forests or fossil fuels
emits CO2 to the atmosphere
Oceans and forests are carbon sinks which
take in more carbon than they release.
Greenhouse Gases: Methane
NOAA Slides by Forecast Systems Laboratory.
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Greenhouse Gases: Methane
• Most of the methane emissions are
from landfills
• Other sources are livestock and fossil
fuel production
http://www.google.com/imgres?imgurl=http://herbarium.usu.edu/fungi/funfacts/
Greenhouse Gases: Summary
• The major greenhouse gas is CO2 but
methane is more potent.
• The other major gases are water vapor
and nitrous oxide.
1996 Total U.S. Greenhouse Gas Emissions
Hydroflourocarbons (HFCs),
perflourocarbons (PFCs),
and Sulfur hexaflouride (SF6)
Nitrous Oxide
1.9% 5.8%
10.0%
Methane
82.3%
Carbon Dioxide
Source: Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 - 1996. U.S. EPA publication #236-R-98-006
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Atmospheric Concentrations of CO2
Mauna Loa, Hawaii 1959-1992
Annual Concentrations of CO2
Z
(ppmv)
360
350
340
330
320
310
300
290
Years
Source: Trends’93 A Compendium of Data on Global Change, Oak Ridge National Laboratory, Publication no.
ORNL/CDIAC-65. Mauna Loa data from C.D. Keeling and T. Whorf
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Ozone depletion vs. Greenhouse Effect
• Ozone depletion is caused by the release of
CFC’s (chlorofluoro-carbons) which break
down the ozone layer.
• The ozone layer protects us from harmful
radiation and gamma rays from the sun.
• Climate change due to the increasing
amount of greenhouse gases is a different
problem than ozone depletion.
How Do We Take the Earth’s Temperature?
Weather stations track temperature,
rainfall/precipitation, wind speed, and
barometric pressure on land.
Ocean buoys take
measurements at sea.
Satellites and
weather balloons take
measurements
in the lower atmosphere.
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http://www.google.com/imgres?imgurl=http://earthobservatory.nasa.gov
Air bubbles in ice core samples provide
information of the air composition (CO2) and
temperature throughout Earth’s past.
CO2 measurements from
the ice cores at the South Pole over 1000 years
and direct measurements in Hawaii over 150 years
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Global temperatures are increasing
NOAA Slides by Forecast Systems Laboratory.
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Climate Models - Climate change is a natural
process; periods of colder and warmer climates
• Ice age 6 degrees F colder
• Land ice melts,
rise in sea levels,
mass extinctions 6 degrees F warmer
Scientists predict the earth will warm an
additional 2-6 degrees F by the year 2100
How Humans Influence Climate Models
• Scientists suggest
that humans are
influencing global
climate change due
to data that
population increases
match the increases
in greenhouse gases.
NOAA Slides by Forecast Systems Laboratory.
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Climate Change Evidence
1. Atmospheric gases
of CO2, N2O,
Methane and Water
Vapor are
increasing at a
rapid rate.
2. Global temperature
has increased by 1
degree F in the
past century.
Weird Weather: Global Warming
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3. Extreme weather; more frequent hurricanes,
droughts, and floods.
• El Nino refers to above normal surface
temperatures in the Pacific Ocean that cause
easterly winds to weaken. The cold water is
unable to rise to the surface of the ocean.
This interaction affects weather around the
world, Australia experiences droughts while
USA and Peru experience floods.
• La Nina is below normal sea surface
temperatures.
4. Land and sea ice are melting – decreasing Albedo
• Ocean levels are rising,
(melting land ice) submerging
islands and eroding land.
• Salt water invades (salinity
rates) and changes the fresh
water ecosystems.
• Warm water holds less
oxygen which can suffocate
organisms or organisms
migrate disrupting the food
web for other organisms.
WHY?
• The warmer water prevents mixing of
nutrients and organisms found in colder
waters. This is referred to as an “ocean
desert” and in total is the size of Asia.
• The warm water also can shut down the
ocean conveyor system which cycles
water on our planet.
5. Changes in biome boundaries or disappearance of
habitats; i.e. forests disappearing impacts variety
of species, tundra permafrost, coral bleaching
6. Impacts on organisms; extinction rates increase changes too fast for plants and animals to adapt,
different migrating or nesting patterns
7. Increase in disease carrying mosquitoes in once
colder areas
8. Economic effects – damages from sea level rise
or severe storms
Are Humans Changing the Climate?
Similarities between temperature and CO2 levels
NOAA Slides by Forecast Systems Laboratory.
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U.S. Emissions
Each year, each person in the USA
adds 20 tons of CO2 to the
atmosphere (roughly the mass of 4
elephants or 40,000 pounds)
NOAA Slides by Forecast Systems Laboratory.
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USA is the leading producer of CO2
CO2 Emissions From Fossil
Fuel Combustion: 1996
Million Tonnes of CO2
6000
5000
4000
3000
2000
1000
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Source: CO2 Emissions from Fuel Combustion 1971 - 1996, International Energy Agency, page II.4-5, 1998 Edition
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CO2 Emissions Per Person: 1996
Million Tonnes of CO2
25
20
15
10
5
0
Source: CO2 Emissions from Fuel Combustion 1971 - 1996, International Energy Agency, page II.53-55, 1998 Edition
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Human activities that contribute
greenhouse gases to the atmosphere:
Electricity-burn
fossil fuels
Transportation –
burn fossil fuels
Cutting and
burning forests
NOAA Slides by Forecast Systems Laboratory.
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Increase in human population/demand
Waste in landfills
Livestock waste
Why Should We Care?
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What Can We Do About
Global Climate Change?
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What Can We Do About Climate Change?
Reduce, Reuse, Recycle
Public Transportation, Efficient Cars, Carpool, Bike, Walk
Plant trees and Preserve Forests
Conserve electricity, turn off appliances & lights when not
in use
Use renewable sources of energy
Buy local products
Use fluorescent light bulbs
Use Energy Star Products – Appliances, Windows,
Heating/Cooling
Review: Matching
• Global Warming
• Global Climate Change
• Greenhouse gases
• Absorb sun’s energy
and emit energy in
our atmosphere
• Change in average
weather conditions
in a region over a
long period of time
• Increase in the
Earth’s average
temperature
Review: Matching
•Atmosphere
•Biosphere
•Anthrosphere
•Hydrosphere
• Human construction
(everything we build)
• Includes all of the
water on the Earth
• All life on Earth
• The gaseous layer that
surrounds the Earth
Which 2 factors are the largest
contributors to GCC?
•
•
•
•
•
•
•
Burning Forests
Landfills
Ozone Depletion
Burning Fossil Fuels
Farming
Industry
Breathing
What happens with warm temps?
Oceans
• Ice
• Levels
• Oxygen
• Molecules
• Albedo
• Light changes