Greenhouse Effect

http://education.nationalgeographic.com/education/encyclopedia/greenhouse-effect/?ar_a=1
Recently in our class we have been discussing the greenhouse effect. The greenhouse effect is the trapping of the sun's warmth in the lower atmosphere. The greenhouse effect keeps the earth warm enough so it can sustain life. Some greenhouse gases come from natural resources such as evaporation, swamps, and volcanoes. The Industrial Revolution is the birth of the releasing of larger amounts of greenhouse gases at start. Now the CO2 in the air does not compare to that of a time long ago such as 650,000 years ago.