Imagine that each molecule of CO2 is a feather inside a duvet surrounding the earth. Every time we use more energy we add more and more feathers to the duvet and this in-turn keeps more and more heat in. If we carry on in this manner then things could become very uncomfortable for all earth systems; the same as sleeping with three duvets in the middle of summer.
The general theory of the current global warming trend stipulates that there is a higher concentration of greenhouse gasses (GHGs) accumulating in the atmosphere as a result of human activities. These gases are causing surface air temperatures and subsurface ocean temperatures to rise.
Six main GHGs have been defined. Of these, the primary culprits of global warming through human use are carbon dioxide (CO2) and methane (CH4). During the 1990s, the burning of fossil fuel was responsible for three-quarters of the increase in atmospheric CO2.
For a more in-depth look into global warming and its effects upon earth systems, visit:
Intergovernmental Panel on Climate Change www.ipcc.ch
For Kids and the less technically minded of us www.oneworld.net
The remaining quarter was due to land-use change and deforestation.
GHGs act as a blanket around the earth, without which the earth’s average temperature would be -20° C (less than 0° F). Human activity is making the blanket thicker, limiting its ability to release the heat gained from the sun—a process that helps to regulate temperature.
GHGs allow ultraviolet light (short-wave radiation) from the sun into the atmosphere. But as this short-wave radiation comes into contact with the earth, it is converted into infrared (long-wave) radiation— more commonly known as heat. The GHGs limit this long-wave radiation from escaping back into space.