Global Warming

The Greenhouse Effect
1. The greenhouse effect is caused by incoming light that strikes the earth’s surface causing infrared waves like a giant radiation.
  2. That heat travels unimpeded back out into the void and one fraction of that heat goes back to space. The rest is in the lower air layer which contains a number of gases that absorb infrared variations:
    1. Water Vapor
    2. CO2
    3. Methane
    4. Others
2. Causes: More water evaporates from oceans, lakes and soils. It creates a powerful feedback loop
  1. The hotter it gets, the higher the water vapor content of the air, and the grater the greenhouse effect warming.
Models and uncertainly
1. To project future climates scientists use computer simultations of the interactions among
  1. Air
  2. Water
  3. Land
  4. Ice
  5. Sunlight.
  6. These GCMs consist of equations representing the known laws of
    1. atmospheric physics
    2. ocean circulation
A case of missing carbon
1. Human activity releases 7 billion metric tons of carbon in CO2 into the atmosphere every year. 3 billion of out emissions remains in the air.
  1. The rest is taken by marine and terrestrial plants. Of that “missing” amount of carbon the oceans remove 2 billion from the atmosphere each year.
    1. Aerosols encourage water vapor to condence into tiny droplets. Making the clouds dense and shiny, shading the surface for weeks.
      1. Our own pollution may temporarily have spared us some effects of global warming
As the World Warms
1. The warming anticipated by the IPCC would put a lot more water vapor into air causing more rainfall and more intense weather.
  1. The precipitation will be grater. In areas already prone to flooding or erosion or both that may be a prognosis.
    1. This will affect countries such as Mexico and Africa making them even more arid than they are now.
What drives climate change?
1. Solar Input
  1. Solar energy hits the upper atmosphere at about the intensity of three 100-watt one-third of which is reflected back into space. The rest of the energy warms Earth and fuels its weather engine
2. The Atmosphere
  1. Solar energy hits the upper atmosphere at about the intensity of three 100-watt one-third of which is reflected back into space. The rest of the energy warms Earth and fuels its weather engine
3. The Oceans
  1. Oceans store heat and transport it thousands of miles. When warm water collects in one place, evaporation and cloud buildup increase.
4. The Water Cycle
  1. Higher air temperatures can increased water evaporation and the melting of sea and ice., evaporation leads to cloud formation, which can have a cooling effect.
5. Clouds
  1. they are known to both cool Earth by reflecting solar energy and warm Earth by trapping heat being radiated up from the surface.
6. Ice and Snow
  1. Bright white expanses of ice and snow reflect sunlight back into space, cooling the planet. In the Northern Hemisphere snow cover has decreased about 10% in the past 21 years, but no melting of the Antarctic ice sheet has been detected.
7. Land Surface
  1. When solar energy penetrates the land surface it is converted into heat. Sloping land allows more water runoff, leaving the land and air drier. A tropical forest will soak up CO2, but once cleared for cattle ranching, the same land becomes a source of methane.
8. Human Influences
  1. Human activities magnify warming effects. Ranching, rice farming, and landfills have raised methane levels. Aerosols, such as smoke and sulfate from industry, reflect sunlight and have temporary, localized cooling effects.

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Global Warming

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	Created by Mati Viana about 9 years ago