Though many believe it is a fictional phenomenon, the greenhouse effect has been scientifically proven, the result of a build-up of carbon dioxide within the Earth’s atmosphere. The greenhouse effect occurs when greenhouse gases, particularly carbon dioxide, collect close to the Earth’s surface. The sun’s rays penetrate the atmosphere and are then trapped by the accumulation of carbon dioxide, causing the temperature within the atmosphere to rise dramatically. Some heat is absorbed by the Earth’s surface, only to be radiated back into the atmosphere later. A small percentage of the heat is able to exit the atmosphere, however a larger portion remains trapped in the Earth’s atmosphere.
This diagram depicts the movement of sunlight and the retaining of heat within the Earth’s atmosphere, a simple break-down of the greenhouse effect.
Image Credit: http://www.dinosaurfact.net/extinction/greenhouse_effect.jpg
The greenhouse gases that contribute to the greenhouse effect include nitrous oxide, methane, and fluorocarbon, in addition to the major contributor, carbon dioxide. In the past three centuries, carbon dioxide levels have been on the rise, contributing to the concerns regarding the greenhouse effect. Because of the presence of greenhouse gases within the atmosphere, solar waves are trapped and re-emitted downward, warming the lower levels of the atmosphere more so than the upper levels.
These pie charts show break down the emission of the different greenhouse gases by sector.
Image Credit: http://upload.wikimedia.org/wikipedia/commons/e/e0/Greenhouse_Gas_by_Sector.png