The Greenhouse Effect and Global Warming - PowerPoint PPT Presentation


PPT – The Greenhouse Effect and Global Warming PowerPoint presentation | free to download - id: 44702b-ZTRiN


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation

The Greenhouse Effect and Global Warming


The Greenhouse Effect and Global Warming Diffuse Radiation The Greenhouse Effect Popular name for process whereby greenhouse gases in atmosphere absorb longwave ... – PowerPoint PPT presentation

Number of Views:428
Avg rating:3.0/5.0
Slides: 23
Provided by: ValuedGate271
Learn more at:


Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: The Greenhouse Effect and Global Warming

The Greenhouse Effect and Global Warming
Diffuse Radiation
Diffuse Radiation - Clear skies 80 of
insolation reaches the surface - Cloudy skies
10-45 of insolation may reach the surface
The Greenhouse Effect
  • Popular name for process whereby greenhouse gases
    in atmosphere absorb longwave radiation from
    Earth and then emit or counterradiate it back to
    the surface providing additional heating

The Greenhouse Effect (contd)
  • Process acts to warm lower atmosphere by keeping
    longwave radiation from escaping to space (like
    insulation holding in heat in a house)
  • With no atmospheric greenhouse effect, Earth
    would be much colder current mean global temp is
    15C (59F) w/o greenhouse effect, temps would
    be about -18C (0F), which is a difference of
    33C (59F)...

Greenhouse Gases
  • Gases involved in this process are called
    greenhouse gases
  • All are considered trace gases, meaning they only
    constitute a small percentage of atmospheric
    content, but they play a very important role
  • Include CO2, H2O, CH4, and Water vapor

How Do Greenhouse Gases Get into the Atmosphere?
  • CO2 burning of fossil fuels (coal, oil, natural
    gas) and vegetation, during plant decomposition,
    during volcanic eruptions
  • H20 evaporation, evapotranspiration, airplane
    exhaust, volcanic eruptions
  • CH4 decay of organic matter, human activity
    (rice cultivation, farm animal wastes, bacterial
    decay in sewage and landfills, fossil fuel
    extraction and transportation, and biomass

(No Transcript)
Quick Focus on Carbon Dioxide
  • Charles Keeling started taking CO2 observations
    at Mauna Loa, HI, in 1958
  • Now 45 years of observations what do we see?

A Bit More about CO2
(No Transcript)
Industrial Revolution
  • 1750-Europe, early-mid 1800s in US

(No Transcript)
A Few More Facts
  • CO2 and H2O vapor considered most important
    greenhouse gases
  • CFC-12 absorbs 10,000 times more longwave
    radiation than CO2 (adding one CFC-12 molecule is
    equivalent to adding 10,000 CO2 molecules)
  • CFCs widely used in refrigeration process,
    formerly major component in aerosol spray cans
    (banned in 1976 by U.S. EPA)
  • Liquid water droplet and ice particles in clouds
    also very important in atmospheric greenhouse

NOAAs Viewpoint
Global Warming Debate
  • Its happeningand that is not the debate.
  • Although scientists agree that Earth is getting
    warmer, there is debate about the impact of human
  • Many think human activity is a major cause, while
    others claim its part of a natural cycle
  • Data sources and beliefs

What Natural Processes Lead to Climate Change?
  • Changes in solar radiation solar constant
    variations, 11-year sunspot cycle
  • Astronomical changes 23,000-year precession
    cycle (wobbling of axis), 41,000-year cycle in
    axial tilt, 100,000-year cycle in orbital
    eccentricity (revolution path not always
  • Volcanic activity (Mt. Pinatubo, Philippine
    Islands, April 1994 Fig. 3.25, p. 112)
  • Cloudiness

Warming vs. Cooling
  • Natural cycles can lead to warming or cooling,
    depending on phase of cycle (solar radiation
    changes and astronomical changes) or
    location/time of day in atmosphere (dust from
    volcanic activity and cloudiness)
  • All greenhouse gases tend to cause warming
    (exception is when CFCs destroy O3)

Greenhouse Gases and Global Warming
What Do the Records Show?
  • Problem with observations organized, continuous
    recording of weather only goes back 140 years
  • Have other sources to determine temperature and
    atmospheric composition
  • 1. Tree rings 1 ring 1 yr wider rings
    more tree growth warmer temperatures, more
  • 2. Ice cores drill ice and sample gases in
  • 3. Oceanic sediment cores drill ocean floor
    and look at whats there (including plankton)
  • 4. Reef cores similar to 3
  • 5. Pollen in soil and packrat middens

Temperature Records
Temperature Records
How could global warming affect us?
  • Rising sea levels flooding of coastal/low-lying
    areas, harm water supply, shift in crop patterns
  • Change in growing seasons
  • Warmer temps more evaporation ? drier soils
  • Animal/plant habitat expands or contracts
  • More cloud cover
  • Stronger hurricanes farther north/south due to
    warmer ocean temps