If greenhouse gas molecules were enlarged, this would be their general shape.

The Greenhouse Effect

Have you ever been inside a greenhouse on a cold winter day? It might be cold outside, but inside the greenhouse green plants grow well in the warmth and sunshine. Greenhouses are made of glass and are designed to trap energy inside. The atmospheres of some planets are able to trap energy too. Energy from the Sun can enter the atmosphere, but not all of it can easily find its way out again.

What blocks the Sunís energy from escaping a planetís atmosphere? Molecules in the atmosphere called greenhouse gases absorb the heat.

Without greenhouse gases, the surface of the Earth would be as cold as the surface of Mars. But too many greenhouse gases can cause the temperature to increase out of control. Thatís why itís so warm on Venus.

Earth's greenhouse effect is growing stronger because there are more greenhouse gases in the air. More greenhouse gases are added to the air when fossil fuels are burned. This is causing Earth's climate to warm.

Last modified February 1, 2010 by Lisa Gardiner.

You might also be interested in:

Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more


Most things around us are made of groups of atoms connected together into packages called molecules. Molecules are made from atoms of one or more elements. Some molecules are made of only one type of...more

Earth's Greenhouse Gases

Only a tiny amount of the gases in Earthís atmosphere are greenhouse gases. But they have a huge effect on climate. There are several different types of greenhouse gases, but they all have something in...more

Earth's Greenhouse Effect

Not all of the energy from the Sun that arrives at Earth can leave easily. After being transformed into heat, it can become trapped by certain gases in the air. This is a natural process called the greenhouse...more

Living Things Affect Climate

There are many different ways that the plants, animals, and other living things affect climate. Some produce greenhouses gases that trap heat and aid global warming through the greenhouse effect. Others...more

Volcanic Ash

Ash is formed as a volcano erupts when rocks made by the volcano blow apart into millions of tiny pieces. The rocks are still very hot, because they just formed from lava. If the hot rocks come into contact...more

Cinder Cones

Cinder cones are simple volcanoes which have a cone shape and are not very big. Compare the size of this volcano to the strato-volcano in this image. They are usually made of piles of lava, not ash. During...more

Flowing Lava

Lava can move in two ways, wide flat lava flows, or through channels which squeeze the lava into a small area. The fastest lava flows move at about 6 mi/hr, an easy jog, but they average between 2/3 and...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA