the greenhouse effect
The exception to Earths temperature being in balance is caused by greenhouse gases. But first the role of greenhouse gases in the atmosphere must be explained. Greenhouse gases warm the atmosphere by trapping heat. Some of the heat that radiates out from the ground is trapped by greenhouse gases in the troposphere. Like a blanket on a sleeping person, greenhouse gases act as insulation for the planet. The warming of the atmosphere because of insulation by greenhouse gases is called the greenhouse effect (Figure 1.1). Greenhouse gases are the component of the atmosphere that moderate Earths temperatures.
Greenhouse gases include CO2 , H2 O, methane, O3 , nitrous oxides (NO and NO2 ), and chlorofluorocarbons (CFCs). All are a normal part of the atmosphere except CFCs. Table 1.1 shows how each greenhouse gas naturally enters the atmosphere. Greenhouse Gas Carbon dioxide Methane Nitrous oxide Ozone Chlorofluorocarbons Where It Comes From Respiration, volcanic eruptions, decomposition of plant material; burning of fossil fuels Decomposition of plant material under some condi- tions, biochemical reactions in stomachs Produced by bacteria Atmospheric processes 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 CO2 . Still, CO2 is a very important greenhouse gas because it is much more abundant in the atmosphere.
human activity and greenhouse gas levels
Human activity has significantly raised the levels of many of greenhouse gases in the atmosphere. Methane levels are about 2 1/2 times higher as a result of human activity. Carbon dioxide has increased more than 35%. CFCs have only recently existed. What do you think happens as atmospheric greenhouse gas levels increase? More greenhouse gases trap more heat and warm the atmosphere. The increase or decrease of greenhouse gases in the atmosphere affect climate and weather the world over. Click image to the left or use the URL below. URL:
This diagram illustrates the basic processes behind the greenhouse effect. The greenhouse effect is a natural process that warms the Earth, and, in fact, is quite necessary for our survival. In the shown diagram, arrows display how the greenhouse effect works. Electromagnetic radiation from the Sun passes through the Earths atmosphere. The Earth absorbs these short wavelengths and warms up. Heat is then radiated from the Earth as longer wavelength infrared radiation. Some of this infrared radiation is absorbed by greenhouse gases in the atmosphere. Absorption of heat causes the atmosphere to warm and emit its own infrared radiation. The Earths surface and lower atmosphere warm until they reach a temperature where the infrared radiation emitted back into space, plus the directly reflected solar radiation, balance the absorbed energy coming in from the Sun. The equilibrium of incoming and outgoing radiation is what keeps the Earth warm and habitable.
When sunlight heats Earth's surface, some heat radiates back into the atmosphere. Some of this heat is absorbed by gases in the atmosphere. This is the greenhouse effect, and it helps to keep Earth warm. The greenhouse effect also allows Earth to have temperatures that can support life. Gases that absorb heat in the atmosphere are called greenhouse gases. They include carbon dioxide and water vapor mainly and a small amount of methane and ozone as well. Human actions have increased the levels of greenhouse gases in the atmosphere. The diagram here illustrates exactly what is written above. Apart from Earth, in the Solar System, there also greenhouse effects on Mars, Venus, and Titan. Thus, if it were not for greenhouse gases trapping heat in the atmosphere, the Earth would be a very cold place.
which is a greenhouse gas?
a) carbon dioxide b) water vapor c) ozone --> d) all of the above
volcanic eruptions, decomposition of plant material, respiration, and fossil fuel burning all release this greenhouse gas.
--> a) carbon dioxide b) methane c) nitrous oxide d) ozone
how is the atmosphere like a greenhouse?
a) greenhouse gases reflect sunlight like the walls of a greenhouse. b) water vapor condenses into clouds like droplets condense on greenhouse walls. --> c) greenhouse gases trap heat like the walls of a greenhouse. d) none of the above.
energy that comes off of earths surface,
a) is directly radiated into space. b) is absorbed by greenhouse gases in the atmosphere. c) is altered so that it becomes cooler in the atmosphere. --> d) a & b
all greenhouse gases are emitted by natural processes.
a) true --> b) false
which of these is the most abundant greenhouse gas?
--> a) carbon dioxide b) methane c) nitrous oxide d) ozone
one cfc-12 molecule traps 10,600 times as much heat as one co2 molecule.
--> a) true b) false
atmospheric greenhouse gas levels are increasing due to human activities.
c) true d) false
greenhouse effect is
a) bad for earth because it is warming us up too much. b) bad for earth because it moderates our temperature. --> c) a natural phenomenon that is important for making earth habitable. d) none of these.
what happens when greenhouse gas levels in the atmosphere increase?
a) nothing --> b) the atmosphere traps more heat. c) the atmosphere traps less heat. d) none of the above.
What reduces the amount of energy that the earth gets?
a. The water b. Green house gases c. air --> d. The atmosphere
How many directions does the sun's energy flow?
a. Three b. Five c. One --> d. Two
The Greenhouse Effect consists of how many stages?
a. 2 b. 5 c. 3 --> d. 4
Which of the following elements in the greenhouse effect cause the reabsorption of rays?
--> a. greenhouse gases b. infra-red rays c. atmosphere d. sun
What is shown in the diagram?
a. Nuclear Energy --> b. Green House Effect c. Photosynthesis d. Solar Power
How many processes are involved in the greenhouse effect diagram?
a. 3 b. 5 c. 2 --> d. 4
What do greenhouse gases do?
a. Radiates gamma rays. b. Heats earth's surface. --> c. Traps heat. d. Reflects energy back into space.
Where is the solar energy reflected?
a. Earth b. Space c. Moon --> d. Atmosphere
Which among the following causes the greenhouse effect?
a. Incoming Energy. --> b. Energy trapped in atmosphere. c. Reflected Energy. d. Outgoing Energy.
How many incoming sources of energy coming to Earth are there?
--> a. 1 b. 2 c. 4 d. 3
How many sources of visible light are there in the diagram?
--> a. 1 b. 3 c. 4 d. 2
What is visible light in this diagram termed as?
a. atmosphere --> b. incoming energy c. outgoing energy d. reflected energy
What element of the greenhouse effect is directly affected by human beings?
a. Solar energy b. Atmospheric heat --> c. Greenhouse gases d. Infrared head
How does solar energy contribute to the greenhouse effect?
a. It creates greenhouse gases. --> b. It heats the Earth's surface. c. It lets heat escape into space. d. It traps heat in the atmosphere.
What enters the atmosphere?
a. Greenhouse gases --> b. Solar energy c. Ultraviolet heat d. Infrared heat
Steps of greenhouse effect
a. 4 b. 1 c. 5 --> d. 3
What could happen if too much greenhouse gases accumulate in the atmosphere?
a. All heat might escape into space. --> b. The Earth might become too hot to support human life. c. Solar energy might not be able to penetrate the atmosphere. d. All light might become infrared light.
Where are located the gases related to global warming in the diagram shown below?
--> a. Atmosphere b. Sun c. Sea d. Earth's Surface
In the Greenhouse Effect, what happens to most radiation?
a. it is absorbed and re-emitted in all directions b. passes through the atmosphere --> c. it is absorbed by the Earth's surface and warms it d. is reflected by the Earth and the atmosphere
What is emitted by the Earth's surface?
a. ultraviolet fields --> b. infrared radiation c. solar radiation d. gamma rays
What is absorbed by the earth's surface?
a. Sun b. Light --> c. Radiation d. Water
How many arrows come from the sun in this diagram?
a. 4 b. 3 c. 1 --> d. 2
What happens to the sun's energy in the greenhouse effect?
a. reflected by surface b. reflected by atmosphere c. escapes as radiation --> d. absorbed by greenhouse gases
How many ways can the suns energy escape planet earth?
a. 1 b. 4 --> c. 3 d. 2
What is the main source of energy in this diagram?
a. star b. earth --> c. sun d. moon
What reflects the solar radiation?
--> a. Atmosphere b. Earth c. Clouds d. Stars
Which label shows a process of energy emitted by the Sun?
a. Sun b. Earth --> c. Solar Radiation d. Atmosphere
How many parts are shown in the diagram below?
a. 2 b. 1 c. 5 --> d. 4
How much of the suns rays does our atmosphere prevent from passing?
a. all of it b. some of it c. none of it --> d. most of it
What positive effect does infrared radiation have on the earth?
a. Keeps Earth sunny. b. Makes Earth windy. c. Keeps Earth cold. --> d. Keeps the earth warm enough to sustain life.
What is given off by the earth?
a. gamma rays b. sunlight c. microwave gases --> d. infrared radiation
Almost all energy on Earth comes from what?
--> a. The sun b. carbon dioxide c. space d. infrared radiation
What happens when sunlight passes through the atmosphere and warms the earth?
a. oxygen is produced b. carbon dioxide is produced c. infared radiation is absorbed by earth --> d. infared radiation is given off by the earth
What is emitted by the Earth?
a. greenhouse effect --> b. infrared radiation c. sunlight d. solar radiation