Post on 02-Jan-2016
transcript
Greenhouse Gases absorb IR frequency radiation
• Radiation energy can increase vibration between bonded molecules
• Different molecules will absorb and re-emit different energy levels of light waves as heat
• Greenhouse gasses are gasses that absorb IR energy radiation
Which gasses are greenhouse gasses?• Nitrogen 78.1% • Oxygen 20.9% • Argon 0.9% • Neon 0.002% • Helium 0.0005% • Krypton 0.0001% • Hydrogen 0.00005% • Water vapor 0 to 4% • Carbon Dioxide 0.035% • Methane 0.0002% • Ozone 0.000004% Percentages indicate levels of concentration in Earths atmosphere
• Earth absorbs ultraviolet (UV), visible, and some infrared (IR) radiation from the sun. This heats the earth.
• The earth reflects most IR radiation back towards space and . This process cools the earth.
Absorbtion and Reflection by the Earths Surface
Why is absorbtion of IR a problem?
• If an atmospheric gas can absorb radiation energy it will release that energy as heat energy back into the atmosphere.
• This results in a warmer overall atmospheric temperature.
What if there was no greenhouse effect?
• The earth would be too cold to sustain life.
• Greenhouse gases are required to keep the earth’s temperature above freezing.
Water vapor
• Water vapor is the gas most responsible for the greenhouse effect.
• Human appear to have little influence over its impact on a global scale.
• It’s levels are regulated by rain/snow.
Carbon Dioxide• Cycles normally through photosynthesis,
cellular respiration, and volcanic activity.
• Humans affect carbon dioxide levels in three ways.
– Burning fossil fuels– Burning vegetation– Deforestation
• What is the impact of each?
Does one cause the other?
• More and more evidence says yes, but there is not 100% agreement that the increase in greenhouse gases is causing climate change.
• Unfortunately, the evidence is getting stronger that it does.
Effects of Climate Change
• More extreme weather due do more trapped energy
• Increased sea levels due to loss of ice caps.
• Changes in amount of farmable land
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