Greenhouse Gases and Global Warming. By Chetan P.

Ever been eating an ice cream cone and tje ice cream suddenly falls off? Well you can thank Greenhouse gases for that. Greenhouse gases are located in our atmosphere and they trap the heat radiating out from the earth. So when the sun radiates energy to the earth(shortwave energy) the earth absorbs this energy and expels it back out(long wave energy). From here the air rises into the atmosphere and some of it is trapped by greenhouse gases and put back to earth. Greenhouse gases are Methane, Carbon dioxide, Nitrous dioxide and water vapor (in order from most powerful to weakest). To be classified as a greenhouse gas the molecules must have more than 2 atoms, and it has to be able to trap radiation. The more atoms a greenhouse gas has the more longwave radiation it traps. Since Methane has 4 atoms it traps the most, and since water vapor has only 3 it traps the least.

This diagram shows what happens to the suns radiation when it enters the earths atmosphere.

Evidence for global warming is everywhere. For example the ice sheets are receding, in Greenland they lost 150 to 250 cubic kilometers of ice per year from 2002-2006. This is happening all around the world. Another reason is if you look at the 10 hottest years ever recorded all of them happened in the last 14 years and the hottest year was 2005.(stat from 2006.) Today 2012 was the hottest year. Remember the long drought in the corn belt, caused by global warming.  

                                                                     

The role of CO2  in global warming is huge. CO2 is the most abundant greenhouse gas and it is the second most powerful. Humans take in oxygen and breath out carbon dioxide. There are about 7,118,284,712 people on earth and each person takes about 17,280-23,040 breaths per day and each person expels 0.04g of CO2  per breath. So the average person expels 921g of CO2  per day. So that is 336,384 grams of CO2  per year and the total amount of CO2  per year produced by the human race is 2,394,477,084,561,408g per year. Most of this CO2  gets put into the atmosphere(the other CO2  is absorbed by the trees and turned into oxygen.) The more CO2  in the air the temperature goes up as this graph shows.

Red=Methane, Black=Temperature, Blue=CO2

As you can see by the graph the temperature follows the CO2 levels almost exactly. This shows how much CO2  is produced to affect the temperature so much. CH4 or methane also affects the temperature of the earth. It is the most powerful greenhouse gas but it is not very common. Methane has an incredible ability to trap the incoming radiation and send it back to the earth. This is why temperature levels also follow the increase and decrease of methane in the atmosphere.

The carbon cycle relates to global warming because the more carbon that is produced by humans and animals the warmer the temperature gets. The carbon cycle(as shown below) is a very important part of global warming.

This is a diagram of the carbon cycle.

As you can see from the diagram carbon is produced in many different ways. It is also transported, and released into the atmosphere in numerous ways. It is stored in the atmosphere, ocean surface, deep ocean, coal, soil, sedimentary rocks, sediments, and vegetation. And it is moved from the places it is stored by burning, decomposition, rock formation, weathering and runoff, sinking sediment, deep circulation, phytoplankton, photosynthesis, respiration, and the burning of fossil fuels.  Finally it is moved into the atmosphere by burning, respiration, decay, and the burning of fossil fuels. The primary natural sources of CO2 are decay, respiration and burning and the primary natural sources of CH4 are sea beds, hydrates, clathrates, plant decay, soil and digestion in plants and domestic animals. The primary human sources of CO2 are the factories. These factories produce tons of CO2 emissions each year and there are thousands of factories in the world. The primary sources of CH4 are landfills, factories and the burning of biomass.

Frozen methane deposits are pieces of methane that are in a solid state. These deposits are scattered throughout the earths oceans because these are the places that can keep the methane at a cool enough temperature. The other place that it cold enough to keep the methane solid is the poles, and since the poles are melting this releases the deadly, most powerful CH4 into our atmosphere which makes the earth warmer(because it traps more longwave radiation) which makes the earth warmer which in turn makes more methane deposits evaporate into the atmosphere.