Liz+Doherty

=media type="file" key="Greenhouse Gases Podcast.m4a" width="279" height="279"= =EXTRA CREDIT PODCAST DUE JUNE 1ST= =What are greenhouse gases? Where do they come from?=

Script:
 * Introduction:**

(PICTURE 1-greenhouse) Have you ever been in a greenhouse? Have you experienced the humid, thick air which occupies this shelter of plants? Well, greenhouse gases are not only found in greenhouses, but their effect our atmosphere is similar to the effect they have in a greenhouse. These gases cause the greenhouse at your local florist to become especially humid and warm. (PICTURE 2-atmosphere) The presence of greenhouse gases in our atmosphere is also resonsible for a progressive climate change and temperature increase on our planet, referred to as the greenhouse effect or global warming. (PICTURE 3-global warming)

Now that we know that greenhouse gases are those which trap heat in our atmosphere and contribute to the greehouse effect, also called global warming, we can look further into the specifics of these gases.
 * Greenhouse Gases Broken Down**

(PICTURE 4-Greenhouse gases) The main greenhouse gases include: carbon dioxide, methane, nitrous oxide, and flurocarbons.

(PICTURE 5-carbon dioxide)
 * 1) Carbon dioxide**, or CO2, is a non-flammable gas with no odor or color. It is also the most abundant of all the greenhouse gases.

(PICTURE 6-photosynthesis) Photosynthesis, the production of chemical energy by animal and plants through the absorption of light, allows the recycling of carbon dioxide through the atmosphere.

(PICTURE 5-carbon dioxide, x2) Carbon dioxide comes from the exhalation of humans, burning of fossil fuels, and deforestation.According to envirolink.org, "Every year humans add over 30 billion tons of carbon dioxide in the atmosphere by these processes, and it is up thirty percent since 1750" ([|www.envirolink.org/orgs/edf/sitemap.html]).

(PICTURE 7-cow)
 * 2) Methane** MOOOO! is a flammable gas with no odor or color. It can typically be found in wet areas such as rivers and swamps. Methane is released into the atmosphere from natural and artificial causes. So what's with the cow, right? Natural causes include: the production of methane by bacteria that decompose organic matter as well as bacteria that are found in livestock, termites, and camels. In fact, "In one day, a cow can emit ½ pound of methane into the air. Imagine 1.3 billion cattle each burping methane several times per minute!" ([|http://www.umich.edu/~gs265/society/greenhouse.htm]) Artificial and manmade causes include: coal mining, oil drilling, landfills, and raising livestock.

(PICTURE 8-nitrous oxide graph)
 * 3) Nitrous oxide** has a sweet odor, although it is also colorless. Where does this greenhouse gas come from? Natural sources include: oceans and soil bacteria. In terms of artificial causes of nitrous oxide production, "Each year we add 7-13 million tons into the atmosphere by using nitrogen based fertilizers, disposing of human and animal waste in sewage treatment plants, automobile exhaust, and other sources not yet identified." (World Book Volume 13)

(PICTURE 9-world consumption graph)
 * 4) Flurocarbons.** What a general term. Any organic compound with fluroine and carbon atoms qualifies as a flurocarbon. This opens up the greenhouse gas definition to a more extensive range of gases. It is important to note that these types of greenhouse gases are produced exclusively by human industry. This graph indicates flurocarbons are a world-wide issue contributing to global warming.

(PICTURE 10-refrigerator) CFCs, or chlorofluorocarbons, are a HUGE cause of the release of greenhouse gases into the atmosphere. Since they undergo phase changes from gas to liquid and liquid to gas easily, they are commonly used in refrigerators, aerosol cans, and air conditioners. Do you own at least one of these things? I thought so. These are known as, according to the United States Environmental Protection Agency, as "ozone-depleting substances." The dependency on items containing CFCs such as aerosol cans, refrigerators, and air conditioning units shows just how much humans contribute to the high concentration of greenhouse gases in our atmosphere, creating our universal problem of global warming.
 * Tying It All Together**

(PICTURE 11-stop global warming) Carbon dioxide, methane, nitrous oxide, and flurocarbons, as well as other less common, atmospheric gases surround the Earth, causing it to be 33 degrees C warmer than it would be without greenhouse gases. In the past century alone, the average temperature of Earth has increased by .5 degrees C as a result of the increasing concentrations of greenhouse gases. As inhabitants of this planet, it's our responsibility to do our part by reducing the amount of greenhouse gases we release into the air. The prevention of limiting our release of greenhouse gases is a whole other subject, but now that your awareness of this worldly issue is raised, you can take the first step to saving our planet. So, throw out that aersol can of hairspray and help spread awareness about greenhouse gases! PICTURES: 1. [] 2. www.kidsgeo.com/images/ earths-atmosphere.jpg 3. http://www.solcomhouse.com/images/Global_Warming.gif 4. **www.abcnews.com/sections/us/global106.html ** 5. **www.envirolink.org/orgs/edf/sitemap.html ** 6. [|http://grapevine.net.au/~grunwald/une/KLAs/science/photosynthesis.html] 7. [] 8. **www.envirolink.org/orgs/edf/sitmap.html ** 9.http://www.sriconsulting.com/CEH/Public/Reports/543.7000/fluorocarbons.gif 10. [] 11. []

 [|http://www.umich.edu/~gs265/society/greenhouse.htm] []
 * Sources**