The Greenhouse Effect

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Another textbook definition is: Carbon dioxide and water vapour in a planets atmosphere absorb and reradiate infrared wavelengths, effectively trapping solar energy and raising the temperature - (Essentials of Geology by Lutgens & Tarbuck).

The sun gives off a wide spectrum of radiation and it's a small portion that is in the visible light spectrum that we recognize most. The other rays are X-ray, ultraviolet, etc. One differentiating factor that exists between these forms of rays is the size of the wavelength. Which if you were looking at waves on the ocean would be the distance between the tops of two waves next to each other. The main two categories that are used are long wave radiation and short wave radiation. The earth itself also gives off radiation and it is mostly of the long radiation kind.

Our atmosphere allows certain amounts of the long wave and short wave radiation coming from the sun through to hit the earth and some of the radiation is blocked before entering the atmosphere by the greenhouse gases and particles that are in the atmosphere like salt and dust, called aerosols. The radiation that makes it to the earth is either absorbed or reflected back towards space. It is this reflected radiation from the earth, along with the earths own radiation, and that which it absorbed and is now being given back off that hits the inside of the greenhouse gases.

So the greenhouse gases as well as particles in the atmosphere stopped some of solar radiation from getting to the earth and let some through. As well radiation from the earth heading out to space is in the same situation, some is stopped and some is reflected back at the earth. This is in essence the greenhouse effect, the radiation being emitted from the earth is sent back to the earth by the greenhouse gases in the atmosphere, warming it. This warmth allows for life to exist on the planet which in turn produce the gases to help maintain that balance between the composition of the atmosphere and the temperature that life likes to thrive at.

All life will try to live and if the environment is changing so that life is finding it harder to live, then life will move and try to find a better climate or somehow change the climate back to what it likes. Now that sounds preposterous maybe, but that is what happens. When CO2 gets high and the earth warms and evaporates water more easily, then cloud cover increases from the condensation trapping the heat in and the solar radiation out. As more and more solar radiation is stopped from entering the atmosphere then the earth cannot absorb radiation to give off to be trapped by the same condensation creating a cooling effect. Cooling lessons the amount of water vapour in the air letting the solar radiation back in for absorption, then radiating off to be trapped warming again. The atmosphere, biosphere, lithosphere, and hydrosphere are intimately connected and when one changes, all will. It has taken the earth billions of years of evolution to get to the state where this interconnectedness has stabilized and life has flourished in great variety.

The previous being a hydrosphere example of the interconnectedness of the earth, here is a biosphere example. CO2 is a major component for plant life to live. All life on earth is dependent on plant life not only for food but also because of the role it plays in absorbing CO2 and producing oxygen. The extra amounts of CO2 in the atmosphere creating the global warming on the flip side, has given more CO2 to plant life to feed off of, making them grow faster and bigger. This greater amount of plant life then absorbs more CO2 and might help us in pulling it back down from the higher level. We just need to leave the plant life alive and flourishing to help and not just eat the bigger amount.

This raises an interesting question though that is out of our hands. Does the increase in food for us humans benefit us more than the side effects to humans of a global temperature increase? We have been, currently are, and will learn the answer to this as we continue to live through a vastly changing world in regards to temperature and greenhouse gas concentrations.