Green house effect-
Green house causes Global Warming as it is made in cool places ,so for growing plants Green house is made as it is made of glass so it let the air in but don't let it go ,it traps the sunlight ,so the light can't go from it the place becomes warmer which leads in the melting of ice and causes Global Warming.
Green house effect is the phenomena in which sunlight and heat is trapped in a room or space with the help of objects like glass...and black absorbents....this technology is used in hiily areas and cool regions in herbariums to keep the correct temperature for the plants to grow....these structures are known as green houses...these herbariums are totally covered by glass which absorbs the heat and light from the sun which inturn keeps the interiors warm....this same phenomena can be experienced by entering a car  parked in the hot sun.....this effect and warmth can be increased by regulaters of temperatures and humidfiers...also by maintaining a good balance of carbondioxide and other green house gases....this same principle is used to understand the situation of global warming.                                    (Hope this helps you)