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Global Climate Change

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Title: Understanding Our Environment Author: CCSN Last modified by: Rayne Created Date: 1/16/2002 10:44:40 PM Document presentation format: On-screen Show (4:3) – PowerPoint PPT presentation

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Title: Global Climate Change


1
Global Climate Change
  • Warming of the climate system is unequivocal.
    International Panel on Climate Change, Fourth
    Report

2
Outline
  • The Atmosphere and Climate
  • Convection Currents
  • Greenhouse Effect
  • Weather
  • Winds
  • Frontal Systems
  • Cyclonic Storms
  • Climate
  • El Nino
  • Climate Change
  • Kyoto Protocol

3
The Atmosphere and Climate
  • Weather - daily temperature and moisture
    conditions in a place
  • Climate - a description of the long-term weather
    pattern in a particular area

4
The Atmosphere and Climate
  • Troposphere
  • Ranges in depth from 18 km over the equator to 8
    km over the poles.
  • All weather occurs here.

5
The Atmosphere and Climate
  • Stratosphere
  • Very stable, calm layer of the atmosphere.
  • Used by aircraft.
  • From tropopause up to about 50 km
  • Has almost no water vapor, but 1000X more ozone
    than the troposphere
  • Ozone absorbs ultraviolet light, which warms
    upper part of stratosphere.
  • Ozone protects all life on Earth since UV
    radiation damages living tissues.

6
The Atmosphere and Climate
  • Mesosphere
  • Middle Layer
  • Thermosphere
  • Aurora borealis (northern lights)

7
Layers of the Atmosphere
8
Energy and the Greenhouse Effect
  • Solar Radiation
  • Of solar energy reaching outer atmosphere
  • 25 reflected
  • 25 absorbed
  • 50 reaches earths surface
  • Of the solar energy that reaches the surface,
    much is reflected (albedo)
  • Fresh clean snow 90
  • Dark soil 3
  • Net average of earth 30

9
Energy and the Greenhouse Effect
  • Most solar energy reaching the Earth is near
    infrared (short wavelength).
  • Energy reemitted by the earth is mainly far
    infrared radiation (long wavelength, heat)
  • Longer wavelengths are absorbed in the lower
    atmosphere, trapping heat close to the earths
    surface.
  • Greenhouse Effect
  • Atmosphere transmits sunlight while trapping heat.

10
Greenhouse Effect
  • Gases in the atmosphere, especially carbon
    dioxide and water vapor, are the substances that
    retain heat.
  • Burning fossil fuels releases extra carbon
    dioxide.
  • Deforestation destroys carbon sinks.
  • Positive feedback loop - poles covered with ice
    reflect solar radiation back into space. Now
    that ice is melting, open water is absorbing more
    heat, which in turn is melting more ice, leading
    to more warming.

11
Sources of Greenhouse Gases
  • Carbon Dioxide - fossil-fuel burning
  • Atmospheric levels increasing steadily
  • Most important cause of warming
  • Methane - ruminants, rice paddies
  • Absorbs more infrared than CO2 .
  • Chlorofluorocarbons (CFCs) - refrigerants
  • Declined in developed countries, but now produced
    in developing nations.
  • Nitrous Oxide - burning organic material

12
Sources of Greenhouse Gases
  • U.S. has less than 5 of worlds population but
    produces 28 of carbon dioxide.
  • China, with 1.3 billion people, is second.
  • Japan and Europe produce half as much carbon
    dioxide per person as the U.S.

13
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14
Measuring Carbon Dioxide in the Atmosphere
  • There is a carbon dioxide detector in Mauna Loa
    in Hawaii.
  • This allows measurements far away from cities and
    forests.
  • The winds over Mauna Loa have come thousands of
    miles across the Pacific Ocean, swirling and
    mixing as they traveled.

15
Measuring Carbon Dioxide in the Atmosphere
  • Keelings first measurement, in March of 1958,
    was 0.0314 percent.
  • Slightly higher in the winter.
  • Slightly lower in the summer.
  • Why? Photosynthesis
  • These levels have rose steadily over the last 50
    years.

16
Carbon Dioxide Concentrations on Mauna Loa
17
Weather Happens
  • Weather - physical conditions in the atmosphere
    (humidity, temperature, air pressure, wind and
    precipitation) over short time scales
  • Rain
  • Air cools as it rises, and water condenses as air
    cools.
  • Cooling occurs because pressure decreases as air
    rises.
  • Condensation nuclei (tiny particles) must also be
    present to have precipitation.

18
Ocean Currents
  • Warm and cold ocean currents strongly influence
    climate conditions on land.
  • As surface water moves, deep water wells up to
    replace it.
  • Ocean circulation also driven by differences in
    water density due to temperature and saltiness of
    water

19
Frontal Weather
  • Cold Front - boundary formed when cooler air
    displaces warmer air
  • Cold air is more dense, thus hugs ground and
    pushes warm air up.
  • Warm Front - boundary formed when warm air
    displaces cooler air
  • Warm air is less dense and slides over cool air,
    creating a long wedge-shaped band of clouds and
    precipitation.

20
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21
Cyclonic Storms
  • When rising air is laden with water vapor, latent
    energy released by condensation intensifies
    convection currents and draws up more warm air
    and water vapor.
  • Storm cell will exist as long as temperature
    differential exists.
  • Hurricanes (Atlantic)
  • Katrina in 2005 caused greatest natural disaster
    in North American history.
  • Typhoons (Western Pacific)
  • Cyclones (Indian Ocean)

22
Cyclonic Storms
  • Tornadoes - swirling funnel clouds
  • Generated by supercell frontal systems where
    strong dry cold fronts collide with warm humid
    air
  • Greater air temperature differences in the
    spring, thus more tornadoes
  • Downbursts - disorganized supercells that cause
    downdrafts and straight line winds

23
Cyclonic Storms
24
Studying Climate
  • Ice cores - collected from glaciers reveal light
    and dark bands caused by annual snow accumulation
    on glacier
  • Gas bubbles can be analyzed for atmospheric
    composition.
  • Ash and sulfur deposits correlate with volcanic
    eruptions.
  • Vostok ice core gives us a record back 420,000
    years.

25
Climate
  • Data show that
  • Abrupt climatic change has catastrophic effect on
    living things as organisms are unable to adjust
    before conditions exceed their tolerance limits.
    Species may become extinct.
  • There is a close correlation between carbon
    dioxide concentration and temperature of the
    atmosphere allegedly.

26
CLIMATE CHANGE IS A NATURAL PROCESS
  • Changes in climate have been observed throughout
    history.
  • There have been at least 5 major ice ages.
  • The sun undergoes cycles where it releases
    different amounts of energy.
  • The Earths orbit can shift and tilt.
  • Example Magnitude 8.8 earthquake in Chile
    shorted the Earths day by 1.26 millionths of a
    second.

27
Climate
  • Milankovitch Cycles - periodic shifts in Earths
    orbit and tilt which change distribution and
    intensity of sunlight
  • Ice cores show drastic changes may have occurred
    over short periods of time (years to decades).
  • Volcanic eruptions can cool planet suddenly.

28
Milankovitch Cycles
29
Evidence of Global Warming
  • According to the EPA, the global surface
    temperature has increased 0.9F since 1880.
  • The Earths surface is currently warming at a
    rate of about 0.29ºF/decade or 2.9F/century.
  • The eight warmest years on record (since 1880)
    have all occurred since 2001, with the warmest
    years being 2005 and 2010.
  • Arctic temperatures have increased twice as fast
    as the rest of the Earth.
  • Source http//epa.gov/climatechange/science/rece
    nttc.html

30
Global Warming
  • Range of temperature increase predicted to be
    from 1.1 to 6.4C (2 to 11.5F) by 2100 depending
    on population growth, energy conservation, etc.
  • Best estimate is 1.8 to 4C (3.2 to 7.8F)
  • To put that in perspective, there has been a 5
    degree C rise since the middle of the last ice
    age (about 20,000 years ago).

31
Global Warming
  • Most people will experience more extreme weather
    including droughts, floods, heat waves and
    hurricanes. These extremes have increased
    significantly in the last decade.
  • In the worst outcome, we could see millions of
    human deaths.
  • Sea levels are projected to rise 17-57 cm (7 to
    23 in). If we do nothing, Greenlands ice will
    melt and raise sea levels 20 ft.

32
Global Warming
  • If Greenlands ice melts, a great deal of land
    will be flooded including
  • Most of Florida
  • Some of the Gulf Coast
  • Most of Manhattan
  • Shanghai
  • Hong Kong
  • Tokyo
  • Opponents say cuts in greenhouse gas emissions
    are too costly to business.

33
Is Global Warming Human-Caused?
  • The Intergovernmental Panel on Climate Change
    (IPCC) released its fourth report in 2007.
  • Two important statements are made in the summary
    of this report
  • Warming of the climate system is unequivocal, as
    is now evident from observations of increases in
    global average air and ocean temperatures,
    widespread melting of snow and ice, and rising
    global average sea level. 

34
Is Global Warming Human-Caused?
  • Second statement of the IPCC fourth report
    summary
  • "Most of the observed increase in global average
    temperatures since the mid-20th century is very
    likely due to the observed increase in
    anthropogenic greenhouse gas concentrations."

35
Global Warming Timeline
  • 19th century Beginning of industrial revolution
  • 1958 Daily records of carbon dioxide levels
    start.
  • Venus found to have surface temperatures above
    boiling point.
  • 1970 First Earth day.
  • 1973 Arab embargo -- energy crisis.
  • 1977 Scientific opinion converges on global
    warming as the major climate risk.
  • 1981 Warmest year on record.
  • 1995 Reports on breaking up of Antarctic ice
    shelf.
  • 1997 Kyoto protocol established.
  • 1998 Strong El Nino produces warmest year on
    record.
  • 2003 Deadly European heat wave / major ice
    sheets collapse

36
2005
  • Kyoto treaty goes into effect (not ratified
    by U.S.)
  • Most active hurricane season in recorded
    history.
  • Hurricane Katrina hits New Orleans.

Source NOAA
37
Hurricane Katrina
  • Formed over the Atlantic in August of 2005.
  • Crossed Southern Florida as a category 1
    hurricane.
  • Strengthened very quickly over warm waters of the
    Gulf of Mexico
  • Made landfall over Louisiana as a Category 3
    hurricane.

38
New Orleans
  • Parts of New Orleans are below sea level.
  • The levees holding back the Mississippi river and
    the shoreline were not maintained properly.
  • Immediate connections were made between global
    warming, the unusually warm Gulf of Mexico, and
    the hurricane.

39
2007-Present
  • Severe drought hits Australia from 2007-2009,
    followed by severe flooding in 2010.
  • Severe flooding in Pakistan in 2010.
  • In the last stages of President Bushs term,
    global warming was emphasized as a scientific
    uncertainty
  • In 2009, the U.S. House of Representatives passed
    a bill meant to gradually limit the amount of
    carbon dioxide produced. Stalled in the Senate.
  • In 2009, a series of emails from the researchers
    at the University of Anglia were made public
    some implied data was being manipulated. This
    was nicknamed Climategate.
  • 2010 ties 2005 for the warmest year on record.

40
Evidence of Climate Change is Overwhelming
  • Ave. global temperature climbed 0.6C (1F) in
    last century.
  • 19 of 20 warmest years in the past 150 yrs have
    occurred since 1980.
  • Hottest year since temperature records were begun
    was 2005.
  • Poles are warming fastest (4C, 7F over past 50
    years). Permafrost is melting in Alaska and
    Canada and houses, pipelines and trees are being
    toppled.

41
Global Warming Effects on Poles
  • 99 of sheet ice is located in Antarctica and
    Greenland
  • Ice is melting worldwide, but especially quickly
    at the poles.
  • As a result
  • Ocean levels have risen about 3.0mm per year in
    the 10 years.
  • Adelle penguin population is down to 1/3 its
    normal level.
  • Multiple populations of polar bears are declining.

42
Global Warming Effects on Glaciers
  • Only about 1 of the worlds sheet ice is located
    in temperate (non-polar) regions, but these are
    close in proximity to human populations.
  • Himalayan glaciers are the sources of Asias
    biggest rivers
  • Biggest single source of water for the entirety
    of southern Asia.

43
Effects on the Hydrologic Cycle
  • Surface temperatures are measurably increasing.
    This effects the water cycle
  • Higher rate of evaporation (from land and sea
    both)
  • Warmer atmosphere is capable of holding more
    water vapor.
  • Higher likelihood of heavy precipitation (both
    rain and snow) weather events.
  • Ocean temperatures are also increasing.

44
Flawed Predictions
  • A statement was published by a journal that
    suggested the Himalayan glaciers could be melted
    by 2035.
  • These numbers were based on unrealistic
    calculations and this prediction was retracted.
  • Many dismiss global warming claims in general as
    a result of retractions such as this.

45
Global Warming will be Expensive
  • At present, reducing greenhouse gas emissions
    would cost 1 of world GDP according to Stern
    report. (IPCC report says less than that.)
  • Energy production will need to be 80
    decarbonized by 2050 to stabilize climate.
  • Ethical issue
  • Poor will suffer the most at least 200 million
    people will become refugees of flood and drought.

46
Steps For Combating Climate Change
  • Emissions trading
  • markets already exist
  • Technology sharing
  • Reducing deforestation
  • Helping poorer countries adapt to climate change
  • Tropical areas will not change as much as middle
    and high latitudes.
  • If both Greenland and Antarctica melt, 1/3 of
    Earths population will be displaced.
  • - South Pacific island nation of Tuvalu already
    abandoned due to climate change

47
Combating Climate Change
  • Insurance companies have 2 trillion in insured
    properties along U.S. coastlines at risk from
    flooding or severe storms.
  • Infectious diseases will increase as insects that
    spread them are able to move to places where
    they could not live before.
  • West Nile, malaria, and dengue fever have
    appeared in North America.
  • Melting of permafrost may release stores of
    methane hydrate. Uncertainty about whether that
    would increase warming or cooling.

48
Controlling Greenhouse Emissions
  • Reducing carbon dioxide levels
  • Renewable energy sources
  • Double average fuel economy
  • Switch to efficient lighting and appliances
  • Wind turbines
  • Biofuels
  • Capture and store carbon dioxide
  • Planting vegetation
  • Injection into wells

49
Carbon Management
  • Capturing and storing carbon dioxide
  • Build trees in which calcium hydroxide solution
    would absorb carbon dioxide
  • Plant forests
  • Fertilize the oceans with iron to permit
    phytoplankton growth, which would take up carbon
    dioxide
  • Inject carbon dioxide underground or in ocean

50
Synthetic Trees that Capture Carbon Dioxide
51
Other Ideas?
  • The stratoshield is an idea developed to combat
    global warming by blocking some of the sunlight
    entering the Earths atmosphere.
  • Inject sulfur dioxide or particulate pollutants
    into the stratosphere.
  • This would be too high in the atmosphere to be
    directly breathed or cause acid rain.
  • Blocks out just enough sunlight to bring global
    temperatures down to acceptable ranges.

Another quick solution dropping ice cubes into
the ocean. Source Futurama Crimes of the Hot
52
Progress Made
  • United Kingdom has rolled back its CO2 emissions
    to 1990 levels and is aiming for a 60 reduction
    by 2050.
  • Germany has reduced CO2 by 10.
  • Denmark gets 20 of its electricity from
    windmills, and plans to increase that to 50.
  • China reduced its emissions 20 between 1997 and
    2005.
  • (At its present rate, U.S. will be 25 above 1990
    emissions in 5 years. No progress.)
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