Global warming Phenomenon
If more energy enters the Earth than leaves, the planet will heat up.
Stockbyte/Stockbyte/Getty Imagesby Contributing Writer
Global warming refers to the recent pattern of temperature increases in the earth's atmosphere and oceans, attributed in part to human activity. The scientific evidence for global warming is overwhelming, but the political debate continues. Part of the reason for the continuing debate is that climate science is a complex subject. Climate itself is the result of the interaction among dozens of factors. Because of that, you can't just observe changes in one element and connect them to a specific climatic effect - which makes explaining global warming a challenge.
The Earth receives 84 terawatts of solar power every moment - that's 84 million million watts. Some of that energy is directly reflected from the Earth's atmosphere and the surface of the Earth. Some is absorbed - heating up the air, water and land. The warmer air, water and land emit invisible infrared radiation that heads back into space. But some of that infrared radiation doesn't make it to space - it gets reflected right back to the surface. It's trapped.
A pot of heating water on the stove feels warm and it steams. The heat you feel and the steam you see are both ways the pot is getting rid of energy, but more energy comes in than goes out - so the pot heats up. The same thing occurs with the Earth: If more energy comes in than goes out, the Earth heats up.