The Greenhouse effect and Global warming

The greenhouse effect like a greenhouse keeps things warm for us here on earth. The greenhouse effect works hand in hand with the suns radiation.  Without greenhouse gases the planet would be much colder. Greenhouse gases act like a blanket for earth, this blanket can be found in the layer of the atmosphere we call the troposphere. Greenhouse gases have kept the planet warm by trapping radiation from the earth for billions of years. The only thing is, greenhouse gases are very picky about which kind of radiation they will absorb.

The Greenhouse effect 

The whole process begins when the sun heats the earth.  To put it into more detail,  shortwave solar radiation passes through the atmosphere, this energy makes the atoms of the earth vibrate faster (heat up).  The earth then radiates long-wave radiation or infrared radiation back into space. This infrared radiation is what heats the atmosphere and some of it is trapped by the greenhouse gases.  After the greenhouse gases trap the infrared radiation it is re-radiated back to earth, warming the air. 

               

The following are all greenhouse gases in order from strongest to weakest. Notice how all of these gases contain three or more atoms.

• Methane (CH4) is the strongest greenhouse gas because it has the most atoms. This is why it is the best at trapping radiation, it has more atoms to do so. Even though it is the strongest greenhouse gas it is one of the least abundant.
• Carbon dioxide (CO2) is the second strongest and one of the most abundant greenhouse gases. It is the second strongest because it has the most mass, which helps it to trap heat more efficiently.
• Nitrous oxide (NO2) Is the third strongest greenhouse gas because it only has three atoms and does not have as much mass as carbon dioxide. It is not as efficient as carbon dioxide and methane at trapping infrared radiation, but it is stronger than water vapor.
• Water vapor (H2O) is the weakest because it is the lightest of the greenhouse gases. It often changes into liquid and solid form as well, so it is the least effective at trapping infrared radiation.

      A greenhouse gas needs to have three or more atoms. A greenhouse gas needs to be able to trap infrared radiation and release it as heat energy into the surrounding air. If it does not have three or more atoms and cannot trap infrared radiation it is not a greenhouse gas.

Graph representing ice core data

Ice cores drawn from Greenland, Antarctica, and tropical mountain glaciers show that the Earth’s climate is currently warming. The cause of this warming is greenhouse gas levels. The ice cores can show us the levels of greenhouse gases and how along with the temperature they have also increased very rapidly. Along with the ice cores evidence that the earth is warming can be seen in the sudden sea level rise, the warming of oceans, shrinking of ice sheets, declining Arctic sea ice, global temperature rise, humidity and the retreating of glaciers. Each of these show that the earth is in fact warming. The image above shows data taken from ice cores and how the earth’s climate has changed over the past thousands of years.

                         

                              

Carbon dioxide plays a big role in global warming because it is one of the strongest  and most abundant greenhouse gases.  The more carbon dioxide that is in our atmosphere the warmer it will be.  That is why as carbon dioxide levels in our atmosphere increase, so will the temperature.  On the graph below you can see that the blue line representing carbon dioxide is almost identical to the line that represents temperature. When the carbon dioxide levels increase, the temperature increases. Carbon dioxide traps infrared radiation that is reflected from the earth and releases it as heat into the atmosphere. Since carbon dioxide is the  most common greenhouse gas in the atmosphere temperatures will rise. This means that if carbon dioxide levels in our atmosphere continue to increase, temperatures around the world will continue to increase as well, creating what we call global warming.

                           

Methane is another greenhouse gas that plays a big role in global warming. Methane is the strongest greenhouse gas because it contains 4 atoms, allowing it to trap more heat more efficiently. Even though methane is less common than carbon dioxide it is just as impacting because of it’s ability to trap heat. As you can see in the diagram above, like carbon dioxide the methane mimics the temperature, when methane levels increase so does the temperature.

Since carbon dioxide is one of the causes of global warming the carbon cycle relates directly to global warming. The carbon cycle is the cycle by which carbon dioxide is distributed into the earth’s atmosphere. As more and more carbon is distributed into the atmosphere the more and more the temperature will rise. Below is a diagram of the carbon cycle. This diagram shows both natural and human sources of carbon dioxide. The carbon cycle begins when

carbon is first stored in the deep ocean, sediments, sedimentary rock, coal, oil, gas, vegetation, soil, organic matter and the atmosphere. After the carbon is stored it is then moved by weathering, run off, sinking sediment, rock formation, phytoplankton and deep circulation. This moving of carbon then allows it to be distributed into the atmosphere as carbon dioxide. 

                

                

The primary natural sources of carbon dioxide are decay, respiration and burning. The primary natural sources of methane are sea beds, hydrates, clathrates, plant decay, soil and digestion in plants and domestic animals.

The primary human sources of carbon dioxide are in factories with the burning of fossil fuels. The primary human sources of methane are in the burning of biomass, factories and landfills. Even though this does not seem like a lot of human sources, there are millions of factories and landfills all over the world that distribute methane and carbon dioxide much faster than natural sources.

Frozen methane deposits are large areas of methane, frozen into a sort of ice-like state. If methane is produced quickly enough it will freeze. Most frozen methane deposits are found in ocean sediments, below the seafloor and in some permafrost soils. Frozen methane deposits are found in oceans because the ocean is cold enough to keep the methane frozen.  Another area where frozen methane deposits are found is the Arctic. The Arctic contains a lot of permafrost soil, as global warming melts Arctic ice methane is released into the atmosphere, warming the temperatures even further and giving us even more evidence that methane is the strongest greenhouse gas. Below is an image of places where frozen methane deposits can be found.