global warming

1.in which greenhouse gases, like CO2 in the Earth's atmosphere, cause     thermal radiation emitted by the Earth's surface to be reflected back down .

2.or radiation emitted by the sun to be absorbed  , therefore causing the climate to warm.

3. This is enhanced by man's added pollutants (factories ,cars and  even cows!)

Though…

The greenhouse effect actually doesn't have anything in common with a plant habitat (also called green house)!

the green house for plants works in the principles of convection while the atmospheric green house effect works on the principles of radiation

It is believed by some scientists that global warming due to the greenhouse effect isn't possible as it defies the 2nd law of thermodynamics which is that heat must travel from hotter places to cooler places .