G r a p h i c E d u c a t i o n © Graphic Education 2007 AS/OGGA01 GREENHOUSE EFFECT WHAT IS THE GREENHOUSE EFFECT? 1 The greenhouse effect is a natural process that keeps the Earth warm. Heat energy Reflected energy The greenhouse effect traps heat energy which is produced when energy from the sun strikes the Earth, as heat is trapped in a greenhouse. This is why it is called the greenhouse effect. Atmosphere Earth Energy from the sun Heat energy Reflected energy When energy from the sun strikes the Earth, some is reflected back into space and some is absorbed by the Earth. The energy absorbed by the Earth becomes heat energy. The enhanced greenhouse effect Humans have increased the level of greenhouse gases (methane and particularly carbon dioxide) in the atmosphere. 1.0º 0.0º -1.0º 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 Industrial Revolution Years Temperature in ºC As levels of atmospheric greenhouse gases increase so too does the amount of heat trapped. This makes the Earth hotter. If the level of greenhouse gases becomes too high it could make the Earth too hot to sustain life. The temperature of the Earth has increased since the industrial revolution. It is predicted that the temperature will continue to rise as more greenhouse gases are pumped into the atmosphere. Atmosphere Earth G r e e n h o u s e g a s e s - C a rb o n d io xi d e , w a te r v a p o u r , m e th a n e, n itr o u s o x id e Radiated heat energy escaping the atmosphere The heat energy is then radiated from the Earth’s surface. As the heat strikes the atmosphere some of it is absorbed by greenhouse gas molecules. This keeps the Earth warm.