Global Warming is a phenomenon that is occurring as a result of an excess certain gases being present in the earth’s atmosphere. These gases, known as greenhouse gases, trap the sun’s heat on the earth’s surface. Normally, this is a good thing – it is called the greenhouse effect. However with humans releasing greenhouse gases into the atmosphere at a much faster rate than would occur naturally, the earth’s atmosphere is becoming overloaded. This is resulting in a warmer planet with much less stable climate.
Here is a little illumination from a well-written greenhouse effect/global warming lesson plan from Teacher’s Domain:
“To put this into perspective, consider the temperature difference between now and the last ice age (about twenty thousand years ago): nine degrees Fahrenheit. If the IPCC’s [Intergovernmental Panel on Climate Change] predictions hold, that same temperature change will happen within the next one hundred to three hundred years. Natural cycles of warming and cooling usually take tens of thousands of years, not hundreds. So what’s going on?”
Environmental Protection Agency
Activities that contribute to the more rapid accumulation of these gases in the atmosphere include the burning of fossil fuels, the use of man-made compounds such as sulfur hydroxide and hydrofluorocarbons in industrial processes, and agressive livestock production.
Earth has a natural check and balance system to deal with greenhouse gases; plants and oceans can act as sinks to absorb many greenhouse gases. However, these systems are not able to absorb all of the excess gases and the situation is getting worse. Trees are being cut down at an incredible rate and due to the melting of places like the Artic tundra, greenhouse gases that have long been sequestered are now being released into the atmosphere.
Here is a nifty little video that explains everything much better than myself from the folks at National Geographic:
If you want even more information, here is a video of a lecture from the University of California. It is an hour long, but good:
