Greenhouse effect and global warming

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Lecture 3

• Greenhouse effect and global warming
• Consequences and solutions of global warming
• Global sulfur cycle and acid rain

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For a gas molecule to absorb IR radiation

• Its vibrational frequency (????) must fall within
  the IR region (particularly the thermal IR
  region, 4-50 µm)
• Its vibrational motion must produce a net change
  in dipole moment (???).

Note that energy transition of vibrational motion
is quantized, so is rotational motion.
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Molecular vibration for a non-linear molecule
such as H2O
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Molecular vibration for a linear molecule such as
CO2
Symmetric stretch
Bending 15.0 µm
Asymmetric stretch 4.26 µm
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Absorption Spectrum of different greenhouse gases
in the thermal IR region
For a photon E h c / ?
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Malaria Mosquito
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Katrina 2005
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Coral Bleaching
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Aerosol particles(???????? )

• Mainly from combustion of fossil fuels, e.g.
  carbon particle and sulfate
• Reflect sunlight and cause cooling
• Heavily polluted Eastern China has a decrease in
  maximum temperature of 0.6oC per 10 years.

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Possible solutions

• Minimizing carbon dioxide emissions by using less
  fossil fuel, using fuel with higher efficiency
  (??) and hydrogen-to-carbon ratio, and imposing
  carbon taxes
• Use alternative renewable energy sources (????)
  and use energy more efficiently
• Carbon sequestration (??) injecting CO2 in deep
  oceans or underground iron fertilization
  growing plants so storing carbon in biomass