In the greenhouse effect, Earth's gaseous atmosphere traps heat energy from sunlight and the planet's temperature increases. Scientists first theorized about Earth's greenhouse effect in the 1820s, but no one saw it as a problem until the 1950s, when a few researchers speculated that technology might be accelerating the rate at which Earth traps heat. Now there is international concern that the greenhouse effect leads to global warming and climate change. These unprecedented changes have the potential to affect rainfall, plant life, the level of the seas, and ultimately the life cycles of all plant and animal species.

Water vapor is one of the major gases that helps generate the greenhouse effect. Other greenhouse gases include carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons (CFCs). The concentration of these gases has been observed to be increasing, and scientists believe that this increase of gases is a direct...