Cartoon Earth inside a greenhouse

How is Earth a greenhouse?

Earth's atmosphere does the same thing as the greenhouse. Gases in the atmosphere such as carbon dioxide do what the roof of a greenhouse does. During the day, the Sun shines through the atmosphere. Earth's surface warms up in the sunlight. At night, Earth's surface cools, releasing the heat back into the air. But some of the heat is trapped by the greenhouse gases in the atmosphere. That's what keeps our Earth a warm and cozy 59 degrees Fahrenheit, on average.

Drawing shows Earth, surrounded by atmosphere containing greenhouse gases, and Sun shining through. Labels say 'During the day, when the sun's energy reaches Earth's atmosphere, most of it goes right through. Some bounces off, back into space. At night, most of the Sun's energy escapes back into space. But some is trapped inside the atmosphere by the greenhouse gases, further warming Earth.

Greenhouse effect of Earth's atmosphere keeps some of the Sun's energy from escaping back into space at night.