10.16: Greenhouse Effect
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How does the atmosphere resemble a greenhouse?
Farmers use greenhouses to extend the growing season. A greenhouse traps thermal energy. Days
The Greenhouse Effect
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Gases that absorb heat in the atmosphere are called greenhouse gases. They include carbon dioxide and water vapor. Human actions have increased the levels of greenhouse gases in the atmosphere (Figure below). The added gases have caused a greater greenhouse effect. How do you think this affects Earth’s temperature?
Human actions have increased the natural greenhouse effect.
Like a blanket on a sleeping person, greenhouse gases act as insulation for the planet. The warming of the atmosphere is because of insulation by greenhouse gases. Greenhouse gases are the component of the atmosphere that moderate Earth’s temperatures.
Greenhouse Gases
Greenhouse gases include CO2, H2O, methane, O3, nitrous oxides (NO and NO2), and chlorofluorocarbons (CFCs). All are a normal part of the atmosphere except CFCs. The table below shows how each greenhouse gas naturally enters the atmosphere (Table below).
Greenhouse Gas | Source |
---|---|
Carbon dioxide | Respiration, volcanic eruptions, decomposition of plant material; burning of fossil fuels (driven by humans) |
Methane | Decomposition of plant material under some conditions, biochemical reactions in stomachs |
Nitrous oxide | Produced by bacteria |
Ozone | Atmospheric processes |
Chlorofluorocarbons | Not naturally occurring; made by humans |
Different greenhouse gases have different abilities to trap heat. For example, one methane molecule traps 23 times as much heat as one CO2 molecule. One CFC-12 molecule (a type of CFC) traps 10,600 times as much heat as one CO
Summary
- Greenhouse gases include CO2, H2O, methane, O3, nitrous oxides (NO and NO2), and chlorofluorocarbons (CFCs).
- Greenhouse gases trap heat in the troposphere. Some greenhouse gases can trap more heat than others.
- Levels of greenhouse gases in the atmosphere are increasing due to human activities.
Review
What effect does insulation have on global temperature?What is insulat ion? - What is the greenhouse effect?
H ow does Earth's atmos phere resemble a greenhouse?