Climate Forcing
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- Are factors in the climate system that either increase or decrease the effects to the climate system.
- Positive forcing such as excess greenhouse gases warm the earth negative forcing, such as the effects of most aerosols and volcanic eruptions, actually cool the earth.
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Natural Forcing’s
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- Include changes in the amount of energy emitted by the Sun, very slow variations in Earth’s orbit, and volcanic eruptions
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Human-Induced Forcing’s
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- Activities include greenhouse gas and aerosol emissions from burning fossil fuels and modifications of the land suface, such as deforestation Greenhouse gases are a positive climate forcing; that is, they have a warming effect
- Carbon dioxide emitted from the burning of fossil fuel is presently the largest single climate forcing agent, accounting for more than half of the total positive forcing since 1750 Burning fossil fuels adds aerosols to the atmosphere.
- Aerosols are tiny particles in the atmosphere composed of many things, including water, ice, ash, mineral dust, or acidic droplets.
- Aerosols can deflect the Sun’s energy and impact the formation and lifetime of clouds. Aerosols are a negative forcing; that is, they have a cooling effect.
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Estimate the effect of each gas ( three main factors)
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- How much of these gases are in the atmosphere
- How long do they stay in the atmosphere
- How strongly do they impact global temperatures
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